SLOW Twists and FAST Casts Using CUSTOM Barrels...Results, Please?

[cainttype]

After tiring of losing the ability to follow the results of tests being conducted by members here using custom barrels with slower-than-normal twist rates, usually because "RPM" is mentioned, I decided to give those slow-twist test results a thread of their own.
Please feel free to discuss any aspect of your experiences with these customized rifles, including RPM and any thoughts you may have of the limiting factors it might impose on cast projectiles. Members of the forum interested in exploring these ideas have every right to discuss them openly, without being disrupted by thread removals.
The title says it all, so..... anybody want to post RESULTS?

[cainttype]

MODERATOR help, please?...
I started this post without knowing that Larry Gibson would not be able to contribute in this entire sub-forum. Since Larry's input is critical to the subject this post is attempting to explore, I've copied and pasted the thread to "Special Projects".
Would a moderator please close and/or remove this thread from this sub-forum so that it can be openly discussed under "Special Projects"?

Thanks in advance for any assistance you can provide.

[44man]

Each boolit length needs it's own RPM's. Long ones need faster twists or a higher velocity.
A faster twist can actually handle more boolit lengths. Depends on distances shot too, if 100 and under, a slow twist can be better because a boolit over spun can open short range groups but will settle with long ranges.
Then many shooting cast in rifles shoot very light loads at low velocity so a faster rate is better.
Look at the 45-70 rifle. Many for hunting use 1 in 20" and are very hard to work with, needing a light, fast boolit. BPCR's have 1 in 18" but with the huge boolits, it is still not fast enough. MR made the BFR 45-70 revolver with a 1 in 14" rate and it will out shoot every single rifle made with a large range of boolits.
A 30 caliber will work at 1 in 10" to 1 in 12". Any slower and you might not reach enough velocity for stability. Same with the Marlin .44 mag with a 1 in 38" rate, nothing shoots past 50 yards.
For me, I want a faster twist in any gun, you can reduce velocity if needed but once too slow, you will not get enough speed.

[geargnasher]

The NOE forum has two threads that cover these results exhaustively.

Gear

[onceabull]

And Beyond5.56.com has exhaustive critique of pretty much anything said elsewhere on high velocity with accuracy using cast bullets... Onceabull

[Love Life]

And Beyond5.56.com has exhaustive critique of pretty much anything said elsewhere on high velocity with accuracy using cast bullets... Onceabull

Be careful mentioning other forums. I'd hate to see you get banned.

Have you come across any good deals on cool guns lately?

[onceabull]

Thanks for the "heads-up". I had surmised that given post #4 above,mine would pass muster...as to new treasures, I'm hurting bad today,after sleeping in and missing GunAuctions# 13241654,only consolation I've come up with is--"it would have probably gone up over $800 if I had got in the game"..Easily the lowest I've seen seen go for...(search closed auctions)... Onceabull

[Love Life]

Right now I'm trolling looking for bullseye built 1911 pistols and old colt 1911 pistols. I need another Norinco so I can play the pimp my Norinco game with 2 guns.

My wife is going to kill me.

[HARRYMPOPE]

Pat Iffland did it 10 or more years ago in CBA matches with success.I dont think he is a member here now.He used a 1-17 twist in a 30x47 with heat treated 165g bulelts at 2900 or there abouts.He did very well,nobody appreciated what he was doing back then.he shot many 1/2" groups as i remember.later on a guy did the same in Unlimited pistol (short rifle XP 100 type) with a 135g LBT in a 30BR at near 3000 fps and won a few big matches.Best way is to research Cast Cullet Assoc. match results.

[onceabull]

Sir: are you saying you are aware of someone who actually shot high velocity cast bullets at matchs with published results,and officials scoring...!!! Onceabull

[swheeler]

I think Pat I. did plenty of research on twist rates and cast bullets, and he is a proponent of RPM threshold as he told me many moons ago. Yes it does exist! As for the 5.56 forum cast section I won't waste my time going there, too much slander, sniping and trolling by the unmentionable one and his minions, but I am working on getting that resolved;-) We'll see

[MBTcustom]

Just for the record, Pat showed me his target backer, and it was indeed impressive.

[runfiverun]

Yeah Pat done it I got a couple of his molds.
Several others have done it other way's
(shrug) big deal.

[bhn22]

There is no one single way to accomplish ones goals with cast bullets. Or practically anything else for that matter. The benchrest guys explore the RPM theory off and on too.

[Bjornb]

The NOE forum has two threads that cover these results exhaustively.

Gear

And that's where the results will have to continue to be posted. This site clearly does not want our shooting posted, or even discussed. I just saw a whole thread disappear, with dozens of posts that took many hours of loading and shooting to create. Luckily I still have the pictures on my computer, mostly with the data written on them.

I don't understand why we cannot have spirited debate and even arguments, these are not subjects where kum-bah-yah is common and there are several schools of thought that all have very opinionated defenders. And so what? I saw no name calling in the XCB thread that disappeared, and none in the Slow Twist thread that was just closed in Special Projects. It's time to put on Big Boy Pants and allow the discussion to cover more than 10 grains of Unique in a 1903 Springfield (no offense to the 1903).

[Love Life]

I'm looking!! I mean, I still suck, but I'm trying!

[cainttype]

And that's where the results will have to continue to be posted. This site clearly does not want our shooting posted, or even discussed. I just saw a whole thread disappear, with dozens of posts that took many hours of loading and shooting to create. Luckily I still have the pictures on my computer, mostly with the data written on them.

I don't understand why we cannot have spirited debate and even arguments, these are not subjects where kum-bah-yah is common and there are several schools of thought that all have very opinionated defenders. And so what? I saw no name calling in the XCB thread that disappeared, and none in the Slow Twist thread that was just closed in Special Projects. It's time to put on Big Boy Pants and allow the discussion to cover more than 10 grains of Unique in a 1903 Springfield (no offense to the 1903).

It isn't the membership, Bjorn, there are many here disgusted by the same issues.
The problem is a very tiny group of, for lack of a better term, cyber-bullies. They imploy the exact same tactics each time by starting confrontational exchanges in order to disrupt a peaceful thread. They try to escalate the rhetoric (even over Goodsteel's emphatic apologies, as he attempted to keep the thread discussion civil) to create a false pretense for "moderator intervention", which invariably leads to thread closures or even out-right thread eliminations.
It is simply that they don't want you, or anyone else testing these slow-twist concepts (ESPECIALLY LARRY GIBSON) to share ANY information that might support ideas they've argued against in the past. THEY have decided that none of you guys investing your time, money, and hard work on these tests should be able to post anywhere on this site about your test results... and it appears obvious to me that they have a moderator more than willing to help them silence you all... Thus far, they've been highly successful, and have no reason to stop.

I started the now locked thread specifically to give you guys a small safe spot on this huge forum where you could post freely without the disruptive tactics that ALWAYS seek you out. It was clearly stated from the outset, but that isn't good enough for your cyber-stalkers.
I have sent a review request to the webmaster asking for help in unlocking the thread. I have explained how and why every thread you guys attempt to share your test results in gets axed. I have stated that it is my opinion that there is moderator bias involved. I have asked that there be at least ONE thread available for you guys to be able to post in without being subjected to nazi-like censorship by the tiny group of egocentrics that insist on plaguing you.

I hope that you, Larry, Tim, Sgt.Mike, and every other member here that is interested in what you are doing continue to press for that safe spot for you to post, free of the close-minded bigotry that prevents your input currently. Your work deserves to be documented here, it would greatly benefit the site to have those tests results for future reference.
It's shameful that we've reached this point, but I see no reason to accept things the way they are, regardless of who your test results aggravates... So don't leave, my friend. That would only be rewarding bad behaviour.

[45 2.1]

I don't understand why we cannot have spirited debate and even arguments, these are not subjects where kum-bah-yah is common and there are several schools of thought that all have very opinionated defenders.

No problems with that sentiment, however some of those groups put restrictions (much to their benefit it would seem) on just how it could be accomplished....... when in the context of knowledge of cast, it can be done many ways, not just their way. That's the problem Bjorn.

[runfiverun]

The problem is the bickering.
Discussing high velocity is actually encouraged it's how the details are discussed that brings up the removal of the thread.
Anybody trying to read those threads would give up from the drivel long before they picked up any actual useful information.
I have tried and tried to get this subject out in the open.
It pains me to see the threads being closed, but I can only clean them up and re-open them so many times. (Especially on a work phone)
i dunno any other way to make this happen.

[btroj]

Cyber bullying?

The National Crime Prevention Council defines cyber-bullying as “the process of using the Internet, cell phones or other devices to send or post text or images intended to hurt or embarrass another person.”

[cainttype]

The problem is the bickering.
Discussing high velocity is actually encouraged it's how the details are discussed that brings up the removal of the thread.
Anybody trying to read those threads would give up from the drivel long before they picked up any actual useful information.
I have tried and tried to get this subject out in the open.
It pains me to see the threads being closed, but I can only clean them up and re-open them so many times. (Especially on a work phone)
i dunno any other way to make this happen.

The solution appears too easy to me, just use the same heavy-handed ations that were taken when Larry Gibson was banned from posting in this entire sub-forum... Actually, I don't think it's necessary to even go that far... How about taking just that one thread, as proposed originally, and give the oppressed testers a safe place to post their results and voice their OPINIONS without fear of "moderator intervention".
The only people you'd need to restrict from posting there, to keep the thread on track without the bickering (which we all desire), appears to be any of "The Three Amigos" and 45 2.1.

There is no reason that these results and opinions of all the aftermarket, slow-twist testers shouldn't be archived here, the same as the info being presented in your HV thread continues without interruption.
These members DESERVE the same latitude. It's only fair.

[btroj]

The key word is OPINIONS. If it is expressed as an opinion then nobody cares. Problem is that it is expressed as FACT.

I have no issues with slow twist HV shooting. Looks to me like it works quite well actually. I DO have an issue with the insinuation that it is the "best" or only solution.

Have a thread about shooting and nobody cares. Heck, they can discuss that all they want.

[45 2.1]

The only people you'd need to restrict from posting there, to keep the thread on track without the bickering (which we all desire), appears to be any of "The Three Amigos" and 45 2.1.

Hey Run, since you're one of "The Three Amigos", that means you're Not Welcome, and an affront to a Mod no less. I have the same attitude toward this subject as Brad just posted. If the sales pitch as best and only along with drumming up business was eliminated, there wouldn't be any problem with it.

[runfiverun]

It is an affront.
especially since I was pretty instrumental in designing the round the way it was set-up in the rifles.
I actually meant for the round to be used with a 12-14 twist barrel and at 2600 plus fps around 50-k psi.
Yep easy peasy shooting.

I already have have rifles going 2400 plus but needed something simple to continue testing boolit designs and different lubes with.

If you want to shoot cast at high velocity and make it easy to do so send TiM a rifle a barrel and a check.
if you want to shoot and learn then take the steps laid out in the other thread and learn your rifle alloys, ignition, something about powder relationships , etc then go the other route.
This route is where I got most of my enhanced casting/ shooting knowledge from.

[btroj]

Hey! I have a 12 twist and am shooting over 2600 and around 50K psi.

Woo hoo, I finally did something right!

I am taking the "learn what works" route as it will make me better at casting, loading, and shooting.

[blackthorn]

An OPINION, stated as FACT is still simply one persons OPINION! I hate to see threads closed or removed because some folk get into a disagreement! I, (as is everyone else) am quite capable of sorting out the "wheat from the chafe" after I have read whatever ANY poster has to say! Is there more than one way to arrive at a certain point? Most likely there is, and it is no one's but my decision which route or method (or maybe try all suggested) as to what works for me! This site is hugely popular and in my opinion that is because of it being mostly run on a "as long as it remains respectful, we can advance pretty well anything". I would hate to see this site turn into a place where we have a bunch of "lock happy" moderators shutting down threads for some very questionable "reasons"! This is not THR!

[cainttype]

I have seen no claims about any method being the ONLY way. So that arguement is hollow, as far as I'm concerned.
Suggesting that there is a conflict of interest involved in the manner in which these problems have been handled, intentional or not, seems obvious to me. That's an OPINION, gentlemen...NOT a fact.
If the slow-twist testers are so off-base, why not allow them to post freely, thereby PROVING to the rest of us watching how wrong they are???
Why are they the only people being restricted by thread removals, and thread closures... While their antagonists don't suffer the same treatment???

I understand that moderating a forum like this can be more than a little bit frustrating, and regardless of what others are saying here, I appreciate Run's attempts to keep these threads alive. The simple fact is, I think he's overlooking some causes of the strife, and I believe his friendships MAY have something to do with it.
Any good judge can recognize the POTENTIAL of any conflict of interest, and will voluntarily recuse himself...just in case.

The only thing I'm asking is to provide ONE tiny thread, where these MEMBERS can be as wrong as they want to be... Let them PROVE their incompetence to the rest of us, unchallenged.
I believe the only valid arguements against that proposal are fear and egotism.

Thanks for your efforts, Run, but even you admitted nothing thus far seemed workable.

[45 2.1]

If the slow-twist testers are so off-base, why not allow them to post freely, thereby PROVING to the rest of us watching how wrong they are???

Evidently, you haven't been understanding what was said. I recommend you go back and see what was said instead of depending on memory. To refresh your view, it was said the slow twist was one way of doing HV, not the only way either as some of the slow twisters want people to believe.

Why are they the only people being restricted by thread removals, and thread closures... While their antagonists don't suffer the same treatment???

A former moderator treated several "of us supposedly bad" guys in the manner you now claim that is happening to your group. That guy is not a moderator any more, for unknown reasons. I suppose that he was doing something the PTB didn't like though as evidenced by the circumstances that we saw afterward. Your guys have threads on the CBA and NOE forums that really have went nowhere. People decide what they want to do, not anyone else.

[geargnasher]

Cainttype, I might point out that 45 2.1 was blocked from Special Projects last year. I'd also like to point out that Larry Gibson had enough pull to convince another moderator to post a locked sticky containing only the complete guide to RPM Threshold theory so that it would go un-contested, un-challenged, and un-discussed. How was any of THAT fair? The same opportunity was denied, repeatedly, to anyone else who wanted to describe a different way of doing things. How is that fair?

Yes, there are some serious bullies here, but you don't realize who they really are. They're the same crowd who insists on splitting the ranks and taking sides, pitting one against the other rather than working together, those who make it "us vs. them" in every post, and collect soldiers like for an army to troll the forum 24/7 to disrupt any conversation that doesn't agree with their ideas.

45 2.1 pretty much nailed it in his post above.

And like I mentioned at the outset, one can find plenty of good information on the NOE forum if they're looking for it, only those pursuing the slow-twist, hard bullet, long barrel, custom rifle options are welcome to discuss their ideas over there. Don't believe me on that? I dare you to even try telling that you get sub-moa at 2300 fps out of your deer rifle over there and see what happens. How is that fair?

Gear

[Bjornb]

I have no issues with slow twist HV shooting. Looks to me like it works quite well actually. I DO have an issue with the insinuation that it is the "best" or only solution.



And therein lays some of the rub. I think we can distill ALL of the bickering down to the same tiresome drama that happens EVERY time. Let me illustrate:

Problem when started from the slow twist shooters:
1. Slow twist shooters post groups, explain how it's easily done, use linotype, Goodsteel rifles etc.
2. Fast twist shooters will then post "but you gotta be able to do that in a ten twist" otherwise you're not a real man.
3. Slow twist shooters say "show us the results from your shooting like we did"
4. Fast twist shooters say "we did that in the 1950s and got ridiculed for it"
Now we are at a stalemate, and bickering starts because nobody sees any reason to back down, and mods intervene.

Problem when started from the fast twist shooters: (ex. Milk jug thread)
1. Fast twist shooters post groups or other shooting, explain their methods, soft alloy, bump up bullet in the throat etc.
2. Slow twist shooters will post "we don't believe you, show us proof"
3. Fast twist shooters will, sometimes elaborately, explain the theory, which sounds fine but (IMO) is VERY difficult to achieve (45 2.1 has told the forum many times that it is a process that takes long time and much shooting to achieve, and he is 100% right).
4. Slow twist shooters say "oh you guys are just talk and we don't believe your methods work"
Now we are at a stalemate, and bickering starts because nobody sees any reason to back down, and mods intervene.

I thought cainttype had a good idea when he started the thread in Special Projects for the slow twist followers and other interested shooters. I recognize btroj's right to post wherever he wants to on this forum, but the name of the thread should maybe have tipped him off that this was a thread where his shooting would not be the primary focus (unless he considers his rifle to have a slow twist). So maybe some self-policing would be a good idea for some; there have been many posts in this forum where I scratched my head an thought "huh?", but then I realized that the poster had a right to his opinion, and that inserting mine wouldn't do a darn thing for civil discourse on the forum.

[geargnasher]

Sorry, Bob, apparently my post was redundant.

Gear

[btroj]

It isn't about them proving themselves wrong. They won't. What I DO take issue with is the manner in which tim presented the rpm discussion. Go back and look at and actually READ and COMPREHEND what I challenged him on. He talked about going over a certain rpm and suddenly groups go wonky and you can't keep em on paper. Totally false in many cases.

What I did was present a counter arguement to the entire rpm "thingy". I used logical, targeted points to counter what was presented. I nefer stated or insinuated that using a slow twist barrel is wrong or won't work. What I DID do was counter the idea that using a faster twist barrel is a hindrance to HV accuracy.

I would love a discussion about HV shooting. I don't give two hoots about what twist rate you use. What I want to do is keep the discussion about the shooting, not the twist rate. My barrel is what it is. I want to see what my barrel can do, not talk about what it could do if it was different.

HV shooting is not, and never has been the issue. The sticking point is the rpm "thingy".

[btroj]

Bjorn, that thread took a wrong turn when it stopped being about shooting and became about theory.
Some fail to see that shooting is about making holes in a target, not promoting a theory.

[geargnasher]

And therein lays some of the rub. I think we can distill ALL of the bickering down to the same tiresome drama that happens EVERY time. Let me illustrate:

Problem when started from the slow twist shooters:
1. Slow twist shooters post groups, explain how it's easily done, use linotype, Goodsteel rifles etc.
2. Fast twist shooters will then post "but you gotta be able to do that in a ten twist" otherwise you're not a real man.
3. Slow twist shooters say "show us the results from your shooting like we did"
4. Fast twist shooters say "we did that in the 1950s and got ridiculed for it"
Now we are at a stalemate, and bickering starts because nobody sees any reason to back down, and mods intervene.

Problem when started from the fast twist shooters: (ex. Milk jug thread)
1. Fast twist shooters post groups or other shooting, explain their methods, soft alloy, bump up bullet in the throat etc.
2. Slow twist shooters will post "we don't believe you, show us proof"
3. Fast twist shooters will, sometimes elaborately, explain the theory, which sounds fine but (IMO) is VERY difficult to achieve (45 2.1 has told the forum many times that it is a process that takes long time and much shooting to achieve, and he is 100% right).
4. Slow twist shooters say "oh you guys are just talk and we don't believe your methods work"
Now we are at a stalemate, and bickering starts because nobody sees any reason to back down, and mods intervene.

I thought cainttype had a good idea when he started the thread in Special Projects for the slow twist followers and other interested shooters. I recognize btroj's right to post wherever he wants to on this forum, but the name of the thread should maybe have tipped him off that this was a thread where his shooting would not be the primary focus (unless he considers his rifle to have a slow twist). So maybe some self-policing would be a good idea for some; there have been many posts in this forum where I scratched my head an thought "huh?", but then I realized that the poster had a right to his opinion, and that inserting mine wouldn't do a darn thing for civil discourse on the forum.

Honestly and objectively, I have to agree with that synopsis. You left out the deliberate trolls taking sides and throwing rotten fruit and jeering their particular heroes (oddly, most of them are on the slow-twist/rpm "side" of things, a division that they themselves have created more or less) which always fans the flames, much to their amusement. I submit Sgt Mike, Onceabull, Swheeler, and a few others from the past as examples who never post groups, probably shoot very little, yet participate for their amusement as examples.) I see you're as sick of the whole mess as we are.

Gear

[Char-Gar]

And that's where the results will have to continue to be posted. This site clearly does not want our shooting posted, or even discussed. I just saw a whole thread disappear, with dozens of posts that took many hours of loading and shooting to create. Luckily I still have the pictures on my computer, mostly with the data written on them.

I don't understand why we cannot have spirited debate and even arguments, these are not subjects where kum-bah-yah is common and there are several schools of thought that all have very opinionated defenders. And so what? I saw no name calling in the XCB thread that disappeared, and none in the Slow Twist thread that was just closed in Special Projects. It's time to put on Big Boy Pants and allow the discussion to cover more than 10 grains of Unique in a 1903 Springfield (no offense to the 1903).

That is spoken like a fellow with a short history on this site. Spirited debates and even arguments are regular fare here as long as it doesn't get personal and folks start hurling insults. This particular topic has been discussed over and over again on this forum with much spirit. However there are two long time members here that go at each other every time it comes up. They are neither gentle or courteous in their combat. Neither one seems to have the ability to resist a challenge from the other. There is obvious personal animus every time this comes up.

After years of this, folks have just grown tired of it, as it devolved into a conflict of egos that just happened to manifest itself as ballistic theory and opinions. Now you know the story.

[btroj]

Personal animus is a very polite way of putting it. Very, very polite.

[ShooterAZ]

Sadly, the subject heads for a train wreck just about every time it comes up. There is knowledge to be gleaned, but you have to sort through a lot of "stuff" to get to it.

[cainttype]

The thread in question was started with the idea to simply ALLOW the slow-twist testers to post RESULTS, and allow them to voice OPINIONS... right, or wrong.
The animosity that always arise is simply PREVENTING those results from being posted, and there are many members here that are interested in seeing those results documented HERE.

Gear, if you look at the closed thread it is obvious that my intention was just to provide a small spot where we might finally be able to allow everyone a place to voice opinions, by suggesting (several times) to have totally separate threads running simultaneously.
As far as old grudges or misdeeds, I was hoping we could ALL do better. The thread would still be up and running (as is Run's) if those arguements weren't raised again... How many threads have been handled this way? Why not provide a separate thread, that everyone recognizes represents a single opinion, to go unaccosted in the manner that other threads are running by banning members from participating in?
I know full-well that fairly high velocities ARE achievable in some factory supplied twist rates... I was running a new 270 grain cast from a 24" 1-12 375 H&H at 2400fps last weekend and quit working up from fatigue...there's only so much of that I'm willing to absorb in one day. I have no general use for anything higher than that, in any caliber, but I know it can be done .
That said, I'd STILL like to see how far Larry, Bjorn, and Tim can push their rifles and casts. The problem is it appears unrealistic that we will ever see the entire spectrum discuss HV without moderators having to step in and... well... "moderate".

Why can't we have SEPARATE threads where each viewpoint can be explored without the BS bickering??? It's too easy... Is that it? Too easy?
What reasonable objection to ADDING to the info available here by separating the two camps completely can there possibly be?
We already KNOW that it is the only way...Why not admit it, and let results tell their own stories?
What is there, really, to fear?.... Nothing? GREAT!... Then let's do it, and your support could help make it a simple fix.

[Char-Gar]

Personal animus is a very polite way of putting it. Very, very polite.

I do try and use words that describe yet do not inflame. Over an ice cold Corona beer, I would be much for direct, much more!

[303Guy]

I would like to see what the slow twist, custom barrel guys can do with cast. I think cainttype's suggestion is worthy of implementation. In the meantime all the work being done with fast twist HV has made me interested in seeing what I can do in a Brit and I need something for some of them to do.

Is there a bench rest cast boolit discipline?

[frnkeore]

This particular thread, seems to be setting a record for number of post per minute :) So, I thought I'd try to get one in (but, I'm sure I'll miss a lot while typing) :)

1. There seems to be a common denominator in this problem that has arisen. We'll call it factor "X".

2. As most of you know, I've had my fair (more than) of "conversations" with with the "X" factor.

3. If you take the "I" or "I'm" out of the X factor, it leaves almost no text or content.

4. Yes, some people that are posting in these threads are guilty of BAITING, I have been baited by one of them.

5. If you comminicate using condesending attitudes, things go wrong in a hurry.

6. Respect is assured where respect is given. That is the main thing that the X factor is lacking.

7. For a group of people on this forum, if you disagree with the X, your looked down on and any input you might have is discount or ignored but, facts are facts and are the elephant in the room regarding RPM.

8. Regarding the locked RPM sticky, it's really worthless information. It was done with 3 different rifles, with three different barrel weights and I believe 2 different calibers. It was also done un-scientifically by a person with a predetermined opinion.

9. I'm not a proponant of fast twist, my slowest twist 30 cal is a 12. But, when you see people in competition shooting a 8 twist rifle at 2000+ (almost 190,000 rpm) and another shooting 3300 at 170,000 rpm with the 8 twist being the more accurate, it certainly can make you wonder if the "treashold" is fact or fanticy! It could actually be a hall way (my term) to bigger better things as it doesn't effect accuracy the way it's been stated. Accuracy needs to be come WORSE for it to be fact!!!

10. In defence of production rifles, they are at a disadvantage. With there light weight, recoil control is a issue and the rounded forearms are also hard to control. Plus, no one seems to be willing to rethroat to make them more accurate in aligning and controlling the deformation into the leade with a shollower angle.

11. I think that things could be moderated, fairly well by removing sentences that use the word "I" "my" or "I'm" :)

12. Lets for get about RPMTH, post your info, give us your velocity and your twist rate and NEVER tell anyone that your problem is because your spinning your bullet to fast.

Frank

[44man]

I have seen over spin in action during my varmint days when a blade of grass in front of paper exploded a bullet into a million pieces but it did the same in chucks and crows with just wings floating out of trees. You could hear the bullet hit at 500 yards.
At what point does lead give out from the forces? Does lead get the skin melted off from friction in the bore? Questions I sure can't answer. Yet some get astounding velocities from cast.
This subject will never be a calm one but to argue about it all the time will never get any answers to what is best in each gun and with each boolit.
The only facts I know is if you under spin, your range will get shorter. Over spin will increase short range groups but are better at long ranges. You still need to find what your boolit will take.
I watched too many under spun boolits veer off after so far with a good scope. I have watched over spun rotate around the flight path, then settle or "go to sleep."

[303Guy]

Interesting that you have actually seen these things happening, 44man. I have only seen a 22lr bullet arcing away and the shiny streak of a bullet/boolit as it reflects sunlight on its way to the target. The 22 bullets travelled in a simple arc and the reflected streak was way too quick to see the path. The 22 bullets were with a naked eye. Oh, I have seen air rifle pellets wobble their way to the target (and actually hit), fired from a smooth bore.

Then we've been shown a photo of a boolit that had elongated into a corkscrew shape! It hit the paper sideways.

[44man]

Amazing what you can see with a good spotting scope.

[dtknowles]

I think I have just skimmed over a couple pages of unflattering posts. I could not bring myself to read them in detail, could have done without reading any of them. Nothing to be learned from them. I did not need someone to give me their slant on what they think is going on. I will probably continue to read or at least skim these threads but I will post my groups in my own thread, I will call it 30 BR range report.

Tim

[Hamish]

I would like to see what the slow twist, custom barrel guys can do with cast. I think cainttype's suggestion is worthy of implementation. In the meantime all the work being done with fast twist HV has made me interested in seeing what I can do in a Brit and I need something for some of them to do.

Is there a bench rest cast boolit discipline?

theres not not just a whole nuther world out there, a whole nuther GALAXY,,,,,,

http://castbulletassoc.org/forum/

There is a whole lot of truth being spoken in this thread. One thing I would caution those who have less than five years on this forum. Before assigning blame, spend a couple of months reading all the way back to the beginning of the forum to more fully understand what the present situation actually us, rather than what you think it is.

The TRULY horrifying aspect to all of this is the present and former members of this forum who have already done the work, have the knowledge, and will not post because of what this has all become.

Something to ponder on.

Las I have said before, scrubbing and disappearing threads in an effort to present an absence of discord does nothing but foment an atmosphere of distrust and a belief that true factual discourse is not possible.

[Hannibal]

Thank you VERY much for that link. Now, if you good people will excuse me, I'm off to try and learn something.

[frnkeore]

Thank you VERY much for that link. Now, if you good people will excuse me, I'm off to try and learn something.

Also, click on "Home" (upper left corner) then click "Match Results" and you'll get all kinds of loading info for many 30 cals.

Frank

[45 2.1]

The TRULY horrifying aspect to all of this is the present and former members of this forum who have already done the work, have the knowledge, and will not post because of what this has all become.

Now ain't that just the truth.......................

[pmer]

Interesting that you have actually seen these things happening, 44man. I have only seen a 22lr bullet arcing away and the shiny streak of a bullet/boolit as it reflects sunlight on its way to the target. The 22 bullets travelled in a simple arc and the reflected streak was way too quick to see the path. The 22 bullets were with a naked eye. Oh, I have seen air rifle pellets wobble their way to the target (and actually hit), fired from a smooth bore.

Then we've been shown a photo of a boolit that had elongated into a corkscrew shape! It hit the paper sideways.

We called them vapor trails. The shooter usually doesn’t see them through their scope but a spotter just over the shooter's shoulder can see it in their optics. It helps to be at longer ranges but you can see the arch of the bullet path from shots of 600 yds and more with out too much trouble.

Some factory slow twist shooters would be lever actions like .32 Win. Spl and 35 Rem. Not too hard to get a 32 WS shooting at jacketed velocities with hunting alloys.

[MBTcustom]

I've been on both sides of this. I spent a long time pursuing fast twist (I wish I had been taking it as seriously as I do now. Geez I didn't know how much free floating time I had back then!)
I also have given slow twist a good run for it's money
For the record, I made some Cu alloy, but never really had time to shoot it. (future project)
And I learned to paper patch when I first joined the forum.
I've come a long way since then. I feel like I was still getting over my dorky 20's when I started here, and now I'm a middle aged business owner. That's a little livin right there. Now, I know I have not been here as long as the arguments, but I have been here long enough to figure out that we are all after the same thing. (No, seriously. We are all doing the exact same thing even on a microscopic level.)
You have a hard surface doing damage to a soft surface.
You can either:
Change the angle of the hard surface so that it does less damage to the soft surface.
Or you can modify the soft surface so that the hard surface does less damage to it.
That's so simple a kindergardner could understand it.

That's not what people are fighting about. In fact, it's not a fight at all, it's a feud in the most classic sense of the word, and if it weren't this issue it would be something else.
Some people need to fight to be alive, and considering the number of warriors we have on this forum, I guess I'm not surprised. In fact, most of the people on both sides of this feud used their considerable talents to make enemies of the United States sorry they were ever born, and they don't want some punk who doesn't even know how to throw a decent salute telling them what they can or cannot do with their rifle, and they sure as hell better not tell your friends what is or is not possible.
Others may mot have been in the armed forces, but you know what loyalty is, and how to back your brother's play. I get it.

But if you back up and look at it, why are you doing what you are doing? Are you doing this to win some sort of online battle? If that's the case, I do challenge you to go back in the archives to about 2005 and do that on all the gun boards and you will see this issue being duked out left and right. Most of the gunboards put a stop to it, because they really don't give a rats hind end about cast bullets or the crazy people who want to push them fast, and we have a bad reputation online because of it. This forum alone puts up with HV cast bullet discussions because it's WHY WE ARE HERE.
Unfortunately, it's reached a stalemate. There is no more science or real testing being done for the sake of education. Every shot fired is observed carefully by both sides to see if it can be used as ammunition against the people on the other side of town.
It's the Hatfield's and McCoy's around here anytime we get into these issues. I'm particularly hated because I started on one side of town and decided to go see what the food tastes like on the other side of town. Yeah, I've taken a few pot shots myself, but that wasn't because of what you did to somebody else, it was because of what you did to me personally, and you had it coming (if you think real hard about the circumstances that lead up to it, I'm sure youll smile and say "yeah, I sure did" LOL!).

Look fellers, I'm not here to help with the feud. I never was. I was never in any "camp" and I never will be. I'm sharp as a razor on a few things and dumb as rock salt on others, but I walk my own path. I just do what works and let the rough edge drag, and most of the forum members are just like me. This constant feuding doesn't help anybody, and makes you look like a fool if you engage in it!

Yes, I'll use slow twist barrels when it suits my pleasure. Here's a twist rate calculator from Berger bullets. Punch your cast bullet in there at the speed you desire and tell me what Berger says is ideal for cast lead bullets. http://www.bergerbullets.com/twist-rate-calculator/
I'm shooting the NOE XCB bullet. It's .980 long, weighs 165 grains, and has a BC (roughly) of .287 and I want to shoot it at 2700 FPS. Some of the most accurate rifles I have created had a twist that puts the bullet right on the edge of 1.5 SG stability factor. Berger says 17 twist is optimum for my bullet and my system. Anything faster is drastically over spinning the bullet (sort of like shooting a 300RUM in a 1-8 twist barrel).

That said, a slow twist barrel does nothing for you if you load janky ammo. If you can't get the bullet into the barrel straight, you'll never have excellent accuracy no matter what twist you have on your rifle, and the fast twist crowd says "yeah, and why not use a fast twist barrel as a school master to get excellent accuracy with and learn how to do it with a standard twist?!?!" and I can't argue with that. Excellent idea. However, I don't think, nor have I seen any evidence to support the idea, that you're going to get superb accuracy when you're over spinning the bullet (I'm not talking about 2200 FPS out of a ten twist. I'm more talking about 2700ish and I'm not talking about a 1" group that turns into a 1.25" group. I'm talking about 1" that turns into 12" OK?). If you do, any minuscule error you might make in any casting session will blow your groups, and the accuracy may not be there when you need it.

At that point, you may very well decide to go with a slower twist barrel that allows you to utilize perfect ammunition to the distance you require.
That's where I'm at in this. Looking at the ballistic calculator, I see that all that is required for stability is 1-17 twist as long as I stay above 2500 FPS. Thing is, I don't care to stay above 2500 all the time. Sometimes I may want to shoot slower. So I went with a 1-14 twist. That gives me a SG of 2.29 @ 2700 FPS (still pretty high but not ridiculous), and I want to learn to shoot that twist as blazing fast as I can go in the 30XCB cartridge.

Problem is, I'm tired of standing in the middle and getting shot at because I'm using a barrel I got from a Hatfield, and a cartridge I got from a McCoy!
Am I the only person on this forum who wants to know what happens if you just DO what you know works? (IE: use a meduim twist barrel and listen to what is being done by the HV with standard twist fellers).
Most of you fellers are holding tools and rifles that I made for you, and all I asked for in return was peace. Is that too much to ask?

[btroj]

The problem isn't the shooting. The problem is theory.

I showed specific examples that sorta put holes in the rpm theory. I have a few others prepared if you would like.

What it comes down to is pretty simple. Some hold a theory quite dear and refuse to accept any counter arguement. Even in the face of facts that refuse to beleive the theory is incorrect at best.

While a slow twist MAY make it easier it IS NOT a requirement. That simple statement shows that the rpm theory is dead and needs to be buried.

Yes, you built my rifle. I truly appreciate that. It shoots quite well. I plan to get it to shoot even better by learning what it wants. That said, I do not feel obligated by your generosity to believe in that which is false.

We do not, and never have, disagreed on the idea that the proof is in the pudding. Results matter. Go shoot and see what happens. Where we do disagree is the idea that twist rate is determining factor in HV accuracy with cast bullets. That is the SINGLE area of contention.

I have tried dunking a basketball. Never could. I was happy to touch the rim on occasion. The mere fact I couldn't do it did not tell me it wasn't possible. It merely told me I wasn't good enough. I didn't have the tools to do the job. That is the core issue.

The fact that you, and others, have not managed to get the desired results in a faster twist does not mean th twist was to fault, it simply means you didn't spend the time to find the right combinations. I managed to get somewhat decent groups at speeds that blow away the rpm theory. Even in the face of those results I am told the theory stands? How can that be? I can't ignore the results on targets. I must make a judgement based on the information before me. That judgement tells me that the theory doesn't hold water. As a scientific minded man I can't hold a theory dear when there is obvious evidence that it isn't a valid hypothesis.

We can discuss shooting all day long and have no real troubles. Bring in disproven theory and it will get bad, and fast.

[btroj]

Pages 270 to 272 of "Black Magic, The Ultra Accurate AR-15" by John Feamster third printing.
Accuracy test 5: fast twist vs slow twist barrels.
Using Hornady 40 gr V-max bullets he compares groups fired from a 1-14 and 1-8 barrels. He reduced the charge slightly to improve accuracy from the 1-14 barrel and got an agg from 6-five shot groups at 100 yards of .626 inches at an average velocity of 3747. Switching to the 1-8 barrel he fired at an average velocity of 3805 fps and an agg for 6 five shot groups of .549 inches.
His conclusion- so much for the supposed, horribly detrimental effect of "over stabilizing" the lightweight bullets.

The slower twist barrel was still over 192,000 rpm but the faster twist was at 342,000!

When I see results like this I can only draw one conclusion, rpm has a very minimal affect on bullets as long as they are adequately stabilized. Overstabilization may be a neat theoretical discussion topic but in the real world it just doesn't have a measurable affect on accuracy.

Now can we get back to shooting and leave the theory behind?

[btroj]

http://i1348.photobucket.com/albums/p733/Btroj/imagejpg1_zpsd91ea6ad.jpg (http://s1348.photobucket.com/user/Btroj/media/imagejpg1_zpsd91ea6ad.jpg.html)

"Your bullet is stable and you can expect good groups"

Where does it tell me I am over stabilized and accuracy will suffer?

[btroj]

These far I have used an alloy I think is 50 pounds range scrap with 5 pounds monotype added. I say think as I have been using bullets I cast last fall and like a fool I didn't label them.
I had a bunch of other bullets cast from plain old range scrap I am aging right now. I plan to see how BHn changes affects the accuracy with that alloy. I have a PID controller on order so I can try a range of heat treat temps and get repeatable results. This was based on the testing Rick did with his revolver years ago that showed that above a certain BHn accuracy was accually reduced.

Other than trying this in my rifle with my mould and load setup I know of no way to really know what to expect. I can look at what others use and get ideas on what might work well in my rifle but in the end I need to see what my rifle likes best.

I have other things I want to look into in a similar manner but will keep them mum for now.

This rilfe was intended, at least by me, to be a test bed. I want to see what changes with alloy. What lubes work well? I really want a good, known load for lube testing. A rifle that doesn't throw flyers lets me really know when the lube is to blame.

[sbowers]

The rifling twist/bullet/powder charge is all one equation, and when the limits of that particular combination is reached then there will be a deration of the accuracy. To get more accuracy one of the parts of the equation must be changed. That being either barrel twist/ bullet or powder charge. Shooting one group one time at one yardage does not set a president, you must able to get that same result time and again at multiple yardages before it can be called a successful . If you can not do this then your test mean little or nothing more than you able to get one good group one time. Now this is an ongoing experiment and changes in every part of the equation are a must if the desired results are to be achieved. Arguing that one part of the equation has no relevance to the others is not conducive to getting the point that is being sought.
Steve

[44man]

Good for you fellas.
It all comes around to Greenhill and the thousands of gun rag figures and formulas, all wrong!
Then someone says you need to add this, divide by this or subtract this number. What have they done? They changed the formula to fit what they do. I have pages and pages of this junk and none ever fit what I shot.
The relationship between velocity, spin and your boolit will govern what you do so you must do the work. I refuse to make a twist recommendation because I might shoot 2000 fps and you want to shoot 1000 fps. You shoot 50 yards and another wants 1000 yards.
Maybe the worst question ever to ask is "what twist should I use?"

[btroj]

The rifling twist/bullet/powder charge is all one equation, and when the limits of that particular combination is reached then there will be a deration of the accuracy. To get more accuracy one of the parts of the equation must be changed. That being either barrel twist/ bullet or powder charge. Shooting one group one time at one yardage does not set a president, you must able to get that same result time and again at multiple yardages before it can be called a successful . If you can not do this then your test mean little or nothing more than you able to get one good group one time. Now this is an ongoing experiment and changes in every part of the equation are a must if the desired results are to be achieved. Arguing that one part of the equation has no relevance to the others is not conducive to getting the point that is being sought.
Steve

Ah, but what am I to do with a rifle that has a barrel of a specific twist? I can change many things but the barrel is what it is. I want to focus on getting the most from that one rifle and that means different alloys, powders, and possibly bullets. What I won't change is the barrel.

As for multiple yardafes being required for success, says who? If I want a dedicated 100 yard rifle then why do I care what it does at longer ranges? In this case we all need to form our own definition of success.

[glockky]

I see 45 2.1 is showing banned now. Thats great another wealth of information and excellent bullet designer who did an outstanding job with group buys is now banned. This banning seems to be pretty common anymore.

Several people from this forum who helped me very much starting out are now banned. Guess its time to find a new forum this is getting ridiculous.

[sbowers]

Then obviously you are not willing to make the changes to that will lead the experiment to its obvious goal, which to my knowledge is maxium velocity/ and accuracy from a cast bullets.
Steve

[dtknowles]

another page of useless bickering

just my opinion, at least I kept it short.

Tim

[btroj]

Then obviously you are not willing to make the changes to that will lead the experiment to its obvious goal, which to my knowledge is maxium velocity/ and accuracy from a cast bullets.
Steve

You willing to buy me 4 more Krieger barrels?

Time and money are major limiting factors. This is a hobby, not a job.

[btroj]

True Mike, they also state that their formula isn't accurate for flat based bullets. They say it tends to underestimate stability for flat based bullets.

[sbowers]

There are other barrels that are just as accurate as Krieger and I am almost sure that the builder of the rifle would be acceptable to changing it for the sake of achieving the goals.
Steve

[btroj]

There are other barrels that are just as accurate as Krieger and I am almost sure that the builder of the rifle would be acceptable to changing it for the sake of achieving the goals.
Steve
You are still looking at 800 dollars for 200 dollar a piece barrels. That is no small amount of money. Add in the divorce and it will break me!

[sbowers]

Why is it necessary to have all the barrels at once take them one at a time and work it to it's maxium potential before moving on.
Steve

[btroj]

Brad hey Im asking this again and not nic picing really Im not. when you get the chance run the alloys through a alloy calculator so other can relicate the alloy or have a idea to replicate close to your alloy.
On another topic I seen a calculator that has the correct drag functions for lead if anyone is interested Ill look and post the link.
Brad I know you used bergers site they just dont care about cast and dont offer the drag functions for lead. common and easy mistake.

First- Berger does have a desire to sell their bullets. Right? This stuff is all much more applicable to long range shooters than it is to short range shooters. By short range I mean under 300 yards, certainly under 200.

Second- alloy works out to roughly 1% tin, 3.25% antimony. I say roughly because my range scrap was tested years ago and may have changed and I am using what I believe to be monotype but even then who knows what the exact composition of it is at this point. I don't know how "worn out" the type metal was when I bought it. Good thing is that I have lots of both still on hand so I can get pretty repeatable alloy if I need more.

Third- I think a great many things go into the "real" stability of a bullet. This is why they give things as a range, not as an absolute. What we don't know if those factors have any real world affect on what we are doing. I sorta doubt it. I won't be noticing a .010 difference at 100 yards. Now if i was shooting at 600 to 1000 it matters much more so but I don't have intentions of doing so.

[btroj]

Why is it necessary to have all the barrels at once take them one at a time and work it to it's maxium potential before moving on.
Steve

Time will tell? Let me get this barrel figured out before I commit to anything.

[Blammer]

so is any one going to post any results?

[btroj]

so is any one going to post any results?

I have posted what I have shot. Look at the HV thread here by Run. Weather took a typical NE turn and got cold and windy so I haven't been out for a bit.

I have been using the heck out your checks! I may need to order another 5K 30 cals.

[Larry Gibson]

A while back I shot the calculator that would do GL function to Bjornb Ill see if I can dig it up.
and I will say realllyy and truthfully the Calculators are a guide.
The bore dimentions (land / groove dia and widths) will change how the twist affect the stability or at least that is what a respect barrel maker has told me. I just never doubted his word. Now is that a myth or fact I dont know

Comparing actually measured BCs (the M43 Oehler can do that) and their actual drop figures measured by actually shooting at ranges to 400 yards I find the standard G1 function to be the closest for use with the flat based bullets we use at velocities over 1800 fps. It's the G function I use in computing the Sg factor based on the Miller Stability Formula.

Larry Gibson

[Blammer]

btroj, better get them while I got them! just got a few 30 cal in the other day.

[btroj]

I may wait til your next shipment, I still have 4K right now. I have used almost 1K this year getting bullets ready for heat treating and what now. That last bag went pretty fast....

[Larry Gibson]

so is any one going to post any results?

I'll be posting some test results (shot yesterday) as soon as I get the post prepared.

Larry Gibson

[btroj]

Mike, your inbox is full

[MBTcustom]

Cant wait to see those results Larry.
I've got a buddy blowing my phone up, asking to go shooting (I think he liked it) but I'm covered over this weekend, and I already shot up or gave away all my bullets (if anybody ever hears me say I want a 2 cavity brass mold instead of a 5 cavity aluminum mold, just slap me till I come to my senses!).

Good luck to everybody who's shooting.

[MBTcustom]

These far I have used an alloy I think is 50 pounds range scrap with 5 pounds monotype added. I say think as I have been using bullets I cast last fall and like a fool I didn't label them.

I think I can help you with that Brad. If you can't reproduce your alloy, you're dead in the water. I say this especially if that group you posted in the HV thread was shot with this unknown alloy. You need to be able to get back there if it was a combination that sorta worked.
I can beg a favor from my buddy with the XRF machine.
Funny story there. He came to me a few weeks ago in a panic and told me that he had lost his titanium wedding band and his wife was about to kill him. He showed me pictures of the original, and I cut him a new one out of titanium. A couple hours under a microscope with a graver rendered a very fine band that looked better than the original. Yeah, he owes me big time. LOL!

[cbrick]

It would be much easier to keep stuff on your bench if you would use it this way. :mrgreen:

130747

[btroj]

Rick, I have little baggies full of bullets with writing in the baggie. This is part of the reason I did my cleaning a few weeks back. I had so many bullets I wasn't using any more and they needed to go away. 265 pounds worth

[MBTcustom]

I've seen Sarge's loading bench. He messed it up so as not to make people feel bad. LOL!

Sarge, I have a chronograph here I'm not using this weekend. Feel free to come borrow it. I'll even let you take my bipod.
(just give me a few minutes to weld some steel plate to it) LOL!

[44man]

I see 45 2.1 is showing banned now. Thats great another wealth of information and excellent bullet designer who did an outstanding job with group buys is now banned. This banning seems to be pretty common anymore.

Several people from this forum who helped me very much starting out are now banned. Guess its time to find a new forum this is getting ridiculous.
I have to ask WHY myself. I truly do not know how I have hung on myself. yes, we lost some good guys and maybe it was from personal attacks. I will attack a process but a few will get nasty and needs a response. But they are not bad fellas. We need to be together even with differences.
Nobody should be banned, Just have a discussion. We all have opinions.
I have gone round and round with 45 2.1 myself but he will be a loss.
I have been a mod and am now a global mod on a site. You have to pee in my boots to get banned by me. Don't PM me and say a guy should be tossed. Personal stuff can be worked out.
I might be the nastiest, most opinionated bastard you ever seen but I respect all of you, personally, I have no better friends then all of you. You can cuss me!
Please bring back 45 2.1.

[Larry Gibson]

Took Dawn (BRNA VZ24 M98 barreled with a 31" Broughton barrel with 16" twist) out yesterday as I had recently made up 100 new 30x60 XCB cases and loaded them with some LBT 150 gr SPs cast of #2 WQ'd alloy. I consider these as "culls" because the original sprue plate was not cutting clean, pretty jagged actually. Thus I just kept them for such a purpose. Goodsteel subsequently made a new sprue plate that works excellently BTW. I did not weight sort the LBTs but only did a cursory visual inspection . The last of my Blammer GCs were used and they were sized at .311 and lube with 2500+. I loaded them in 10 shot strings over 4895. Ten shot test strings were used going from 37 gr to 46 gr. Winchester 30-06 cases were used to form the 30x60s and other than initial forming and turning the necks no other match prep was done. I also only used the M35P Oehler chronograph for this test as fire forming the cases was the primary goal with a base line of velocity potential being the secondary goal. The start screen was 15" from the muzzle and 18 - 20 fps can be added to the instrumental velocity to get close to the muzzle velocity.

130761

The 1st cold clean bore shot with the 37 gr load went low and away as expected. The 2nd shot also was slightly low out of the group but I counted it anyway. Group size was 2" at 2578 fps.

The 38 gr load went into 1.48" at 2645 fps.

I called the 1st shot low left on the 39 gr load and it was so I discounted it from the group. The remaining 9 shots went into 1.44" at a recorded 2689 fps.

With 40 gr the velocity was 2747 fps with a 1.55" group.

At 41 gr the group was 1.6" at 2802 fps.

The above groups had a Dacron filler. The following did not as load density with the thrown powder chargers was at 85%+.

130759

Then things went south...........fast!

The 42 gr load opened up to 2.7" at 2775 fps.

The 43 gr load opened to 6.6" with one really bad flyer. Velocity was 2822 fps.

At 44 gr the velocity was 2881 fps and the groups size was 2.65". Now some might yell and shout about that but in reality, given the previous group and the 2 groups following it just happened to be a smaller group.

The 45 gr load clocked 2948 fps with a group size of 5.8"

And lastly the 46 gr loaded pulled in at 2991 fps (3000+ fps if corrected to the muzzle) with a scattered 7" group.

130762

As I stated originally in the original 30 XCB thread one my objectives with the 16" twist barrel would be to see how far we could push #2 alloy before it's structural strength was severely compromised. Now with 2 bullets (the 30 XCB and the LBT 150) cast of #2 alloy pushed to 3000+ fps I've found that objective. It appears #2 alloy holds up quite well to an acceleration rate of 2700 - 2900 fps depending on the bullet design, the twist and the powder burn rate used. Some where in there the alloy begins to plasticize under the 48 - 50,000+ psi required to reach those velocities. I'll move on to another alloy (linotype) and push it as far as I can in the 30x60 XCB with the 30 XCB bullet and the LBT bullet. I have already pushed the 30 XCB bullet to 3100+ fps at 56-57,000 psi.

Another objective of the 30x60 XCB with the 16" twist was to achieve 2 moa or less accuracy at 2800 - 2900 fps while maintaining linear dispersion at extended ranges. That objective was met within the first 150 rounds fired out of Dawn with 2 different cast bullets of #2 alloy. More testing to follow.

Larry Gibson

[Larry Gibson]

Mike

Yes, I mix it using the Lyman formula using linotype, lead and tin.

Larry Gibson

[44man]

Am I still here, seems I can't post.

[Bjornb]

Yeah you definitely reached the limit for the alloy. I couldn't make it happen in my rifle with fixed ammo, ran out of powder space. But with the breech seater we moved into linotype territory quickly.

[Bjornb]

Am I still here, seems I can't post.

You're here 44man, you haven't been banned........yet

[btroj]

I think I can help you with that Brad. If you can't reproduce your alloy, you're dead in the water. I say this especially if that group you posted in the HV thread was shot with this unknown alloy. You need to be able to get back there if it was a combination that sorta worked.
I can beg a favor from my buddy with the XRF machine.
Funny story there. He came to me a few weeks ago in a panic and told me that he had lost his titanium wedding band and his wife was about to kill him. He showed me pictures of the original, and I cut him a new one out of titanium. A couple hours under a microscope with a graver rendered a very fine band that looked better than the original. Yeah, he owes me big time. LOL!

I made 110 pounds of that stuff last fall. That would make over 3000 bulelts. That is a heap of shooting. If it works I can whip up another 200 pounds pretty easily.

I may send you a sample of the monotype. I had it tested years ago but don't trust the results at all.

[cbrick]

Jim, you were probably trying to post in a thread that went poof. Like the revolver accuracy thread.

Your post here most definitely looks like a post to me. :mrgreen:

Rick

[btroj]

I didn't get a PM?

I haven't shot the 190X in a while, I am currently using the MP 30 Sil.

The 190X has similarities to the 30 XCB bullet by NOE, the 30 Sil is very different. The 30 Sil is designed to let the pressure alter the bullet in a specific manner. This in general requires a lower Sb alloy. That bullet also prefers to be seated off the lands. The 190X is a strong, morse taper type fit in the throat. Like the NOE bullet it will prefer to be on the lands, I suspect.

I find it hard enough to find time in this weather to test one bullet, trying 2 or 3 would border on impossible.

[Rattlesnake Charlie]

I've enjoyed this website ever since I first found it.

I've learned much, and hope to continue to do so.

I enjoy reading about each different approach.

I do wish we could enjoy all ideas and opinions here without flaming.

Our goal should be to expand the knowledge and boundaries of shooting cast boolits.

Let us not destroy a good thing.

[44man]

Jim, you were probably trying to post in a thread that went poof. Like the revolver accuracy thread.

Your post here most definitely looks like a post to me. :mrgreen:

Rick
Might be. Got a thing from the administrator but the posts might have been kaput.

[MBTcustom]

I didn't care for the MP 30 SIL personally. Beautiful mold, and it cast very consistent bullets, but there was an awful lot of unsupported nose on that one. Then again, that was back when I had the janky 10 twist barrel.....
Hmmmm
I agree with Brad here. One bullet design with several choices of lube, alloy, and seating depth, could keep a guy busy for several months of hard testing before he might tentatively venture an opinion on it's merit or lack thereof in one rifle.
That said, there have been plenty of designs that just suck rocks and it only took one range session and a bit of reading to come to that conclusion.
I designed the XCB bullet to be absolutely the best mid to high speed bullet right off the bat, and so far, it's been a rave success. (it surpassed my wildest expectations.) I'll be ragging it out for a while.

[btroj]

But that unsupported nose is designed that way. It doesn't stay unsupported for long if the alloy is right.
I wish my berms allowed for better recovery of spent rifle bullets. The clay is pretty hard on them unless a bit damp and then they just burrow forever. Seeing how much of the nose engraves would tell a bunch about how the specific alloy responded to the pressure.

[MBTcustom]

Trust me, that's something I have wanted for a long time. But the lead is so soft (even made of HT alloy) that just shooting through a light fluffy material at HV will damage the bullet terribly.
I had in mind to buy a long cardboard pillar form, blow insulation into it, set it out at 500 yards, and try to lob a boolit in there to catch it. Let the air take care of slowing it down, and let the insulation take it from there.
Unfortunately, that requires me to be able to hit a 12" circle at 500 yards with a cast bullet, and that is nigh impossible with a fast twist barrel. Or at least it was for me.
Matter of fact, that's a really good idea! Recon you could lob one in there Brad? I would like to see if a bullet could be caught in that fluffy stuff.

[btroj]

I wish it was that easy! I will be able to find some come summer when it dries out but they generally have the nose eroded away from impact. I may need to try some at longer range and see how they look. Will need to find a day when I have the range to myself, maybe a late evening.

[Yodogsandman]

Can't you load it to lower velocities for that? Then shoot into your medium close in.

[btroj]

Won't work, not the same pressure lefel or pressure curve. Pressure is what makes the metal flow so unless we have the same pressure it tells us little. What bullet recovery would let us see is how each bullet was changed by the firing process.

A high speed camera setup would be helpful too but they aren't cheap, least not a good one.

[MBTcustom]

$50,000 IIRC. That'll hair lip a country boy.
I did some testing with cat sneeze loaded when I was designing the XCB bullet, shooting all my 30 caliber designs into a sand box and recovering the bullets. I learned a thing or two about engraving and how the bullet reacts, but Brad is correct, the only way to know what happens to a bullet when fired with a specific full house charge of powder is to recover a bullet that had suffered that trauma. Unfortunately, the very thing that's affecting the alloy and making it work the way we think it might, is the very thing that makes it so hard to recover.
Its like trying to measure a smoke ring with a pair of calipers.

[runfiverun]

I can get one in a less than a 4" circle with no problem at 300 yds.
Unfortunately it only has a 2400 fps muzzle velocity.
Dr. Mann used oiled sawdust back in the day I prefer snow except for the finding them part.

[btroj]

We don't have that kind of snow. I'm OK with that.
A light, finely divided powder mght work but it would need to be pretty deep. Maybe flour?
The realities of the process make it largely impractical. Even oiled sawdust would require large box, lots of oiled sawdust, and a means to get it properly located for shooting into. Longer ranges would be best as the air is the single best non-destructive "slower downer" of bullets in existence.

Like so much of this reality tends to bite one in the keister. I hate that.

[MBTcustom]

LUse the XCB rifle Lamar. You've got a 14 twist on that baby. The differance between 12 and 14 would be very negligible for the purpose of seeing how much % of engraving you get on a reactive bullet. You should be able to get long distance accuracy with the 30SIL at 2600-2700ish FPS without working up too much of a sweat. Will it hold out to 500 yards? Good question.
Recon you could toss a few into something soft and post a picture? I can run some through my rifling die (it's like a Lee PT die but made out of a piece of rifle barrel) and we could do a little long distance comparisons here. We could do a couple other bullets too? I've got the 311466, the XCB bullet, and a couple old Lyman designs you might have also.
Whatcha say?

[btroj]

Recovering rhem from snow is easy, just wait for the melt. Problem is know what each bullet was fired with! Is there a sure fire way to mark the bullets in a way that won't be destroyed?

[MBTcustom]

How about a post marking each snow "berm" with load data?

[oneokie]

Recovering rhem from snow is easy, just wait for the melt. Problem is know what each bullet was fired with! Is there a sure fire way to mark the bullets in a way that won't be destroyed?

Yes there is.



Find one of the micro stamping machines that several states were wanting to use on ammunition sold in their state. :bigsmyl2: [smilie=s:

[btroj]

Yes there is.



Find one of the micro stamping machines that several states were wanting to use on ammunition sold in their state. :bigsmyl2: [smilie=s:

Ah, ask Bloomberg. Anyone got his number?

Marking a snow drift with load data would work. Run probably has plenty of snow. Thankfully we don't.

[runfiverun]

I got snow.
I also have 50 other casters in my town of 2,000 people.
Good luck picking up brass here too, I even have to buy 9mm brass if I want any.

[btroj]

Make sure they don't shoot the same bullet as you? And keep them off your snow bank!

I don't know if we have 50 casters in our club of 2000 members. I hope not, they might start picking my berms. I know of a couple members of the club who are members here too so I have some competition.

[44man]

We had 1/2" of snow and fierce winds all night and today, -16 wind factor. The cold and wind should stop a boolit! :bigsmyl2:

[btroj]

Go shoot a few groups and get back to us.

[Larry Gibson]

Friday I also tested the WQ'#2 alloy XCB over LeveRevolution powder in Dawn. I chose not to use a Dacron filler in the 30x60 like I used with success in the Palma rifle in .308W with 14" twist. It proved to be a bad choice as the internals sucked with the 5 test loads. I loaded 46 to 50 gr LvR in 1 gr increments to test. Even at 50 gr there was sufficient air space in the case for a Dacron filler. The velocity ES ranged from 58 to 116 fps and the psi ES ranged from 4,700 psi to 8,800 psi.....neither very good.

Accuracy with the first load of 46 gr wasn't all that bad at 1.85" for the 10 shots at 100 yards. After that the groups got larger and larger with some serious flyers.......as I mentioned in the previous post I'm finding that 2850 - 2950 fps seems to be the upper limit for #2 alloy. The problem I encounter here around between 2928 fps and 2972 fps was the bullets were shedding the GCs very quickly, like before the bullet got to the screens! I've had bullets occasionally shed a GC but the 47 - 50 gr loads did it quite consistently. If you look closely you can even see some of the stability indicators in the not round holes of the more extreme flyers.

The 46 gr load ran 2873 fps at 44,200 psi, 1.85".
The 47 gr load ran 2928 fps at 45,500 psi, 3.75".
The 48 gr load ran 2972 fps at 47,300 psi, 5.4".
The 49 gr load ran 3025 fps at 51,000 psi, 5.3".
The 50 gr load ran 3103 fps at 56,700 psi, 8.4".

130856


Worse part of the bullets shedding the GCs was it really tore up the screens. Those little 3 gr GCs at 2900 - 3100 fps pack a wallop! Was the right flyer in the 49 gr load that took out the right diffuser. That's when I checked the screens and found all the damage. I'll be casting some 30 XCBs out of linotype and WQing them for further testing. Their BHN should be in the 28 - 30 range and perhaps the GC shedding will cease with the stronger alloy? If you note the 50 gr group at 3103 fps 4 of the shots that went to point of aim appear not to have shed their GCs. That is a sub 2 moa group and is what I'm shooting for (pun intended:lovebooli)

Larry Gibson

130861130857130862130863

[btroj]

How hard would it be to open the check shank just a smidgen? Losing checks is bad, destroying equipment is far worse.

[runfiverun]

Maybe annealing them would work too, it would avoid the uneven spring back rates of the two metals.
Thats why we swage up in size when forming bullets.

[btroj]

Hadn't thought of that but good point Run. Dang it man, you understand this stuff!

[geargnasher]

It takes a sudden and high force to bang an MTF bullet through the throat, my suspicion is the checks and bullet base are getting mangled in the neck, probably getting turned nearly inside out going throat entrance. That's what happens when shooting near-pure lead bullets at a certain point. I'm a little surprised that the tight-necked 30x60 (assuming same reamer as XCB?) is allowing this to happen, but I don't know what the neck clearance is in this setup, either.

One reason I detest the reverse-tapered check shank is that too much goes wrong when that much metal has to move to get the checks crimped on. Using a rebated check shank cures this, and the more pressure that's applied to the bullet base, the tighter the check fits, instead of the opposite.

Gear

[dtknowles]

Here is the Range report for some of the bullets Bjorn sent me.

http://castboolits.gunloads.com/showthread.php?269319-30-BR-Range-Report&p=3139300#post3139300

Tim

[44man]

I hate losing checks but also make mistakes. Made my 30-30 mold and have to tap checks on with a small hammer before sizing. Makes it tedious. I will lap the check area only with a brass lap if too loose.

[Cap'n Morgan]

As promised, a short description of a simple way to form cases by hydraulic pressure:

http://castboolits.gunloads.com/showthread.php?269029-Hydraulic-case-forming (http://castboolits.gunloads.com/showthread.php?269029-Hydraulic-case-forming)

Let's pray it doesn't turn it into a hydraulic vs. fire-forming thread ;)

[Love Life]

Doesn't Hornady make hydraulic form dies?

[Larry Gibson]

Besides running a retest of the 30 XCB bullet over LvR shooting up the last of my cast #2 alloy cast ones I decided to try a couple different bullets of different alloy. Some discussion has been given to the use of the 30 XCB and 30x60 XCB cartridges for hunting. Much discussion has also revolved around the use of a different alloy for hunting purposes.

Well I just happened to have some 150 gr Accurate XCB bullets that were HP'd by goodsteel. They were cast of 50-50 alloy (COWWs = lead), WQ'd and allowed to age some 2 -3+ months. These were sized at .311 with Hornady GCs installed and were lubed with 2500+. No effort was made to weight sort but a good visual inspection rejected some from use. I chose to use IMR4895 with a Dacron filler as that was what was used with the LBT 150 gr bullet and thought it would make for a decent comparison given the bullets almost identical weight. Those were cast of WQ'd #2 alloy and even though used for fire forming cases gave excellent performance (1.6") up through 2800+ fps. I loaded 37 through 42 gr and used a Dacron filler.

From the pictured results you can see the Accurate XCB bullets performed quite well in the 16" twist of Dawn. The 37 - 41 gr loads all were under 2 moa. The 41 gr load began to evidence some problems with some of the holes showing slight bullet tipping and appeared to having crossed the RPM threshold for that bullet/load combination. The 42 gr load confirmed it was indeed over the RPM threshold as the group opened to 3.4" None the less the 40 gr load may be a very good and useable load for hunting to 400 yards IF the expansion of the load remains linear as the range increases. Still though the 30 XCB of 50-50 alloy did not hold up as well as the LBT 150 cast of #2 alloy.

131336131337


Additionally I had some 311041s from a Lee GB mould cast of COWWs + 2% tin and then mixed 50-50 with lead; my usual alloy for hunting .30 caliber cast bullets. These were AC'd and were cast probably 6 - 8 months ago so they were well aged. They weighed right at 170 gr and were sized .311 with Hornady GCs applied. Again no weight sorting was done with only a cursory visual inspection being done. BHN on these bullets is 14 - 15. These were lubed with my own 50/50 alox/beeswax lube using alox 666. These were loaded over 49 - 54 gr of H4831SC with 54 gr being 100% loading density as with these pretty soft bullets I wanted a "slow push".

To say I was mildly surprised and very pleased with the accuracy and velocity in the 16" twist barrel of Dawn would be an under statement! These bullets are hard pressed to do this well at 2200 fps out of my '06s with the same slow burning powders. The 53 gr load gave a muzzle velocity of close to 2700 fps with sub 2 moa accuracy! If that holds at longer ranges I would consider this to be an excellent load for deer and pig hunting to 300 yards where the remaining velocity would still be about 1600 fps with 1000 ft/lbs of energy. For hunting from a stand the longer barrel would not be a hindrance at all.

131338131339



Seems the XCB cartridges just may be a lot more "versatile" than some may think.

Larry Gibson

[btroj]

But it still isn't a 30 BR......

[MBTcustom]

Very surprising Larry. Thanks for posting. Lots to think about.
I can't wait for the new barrels to arrive!
With results like these, long range hunting with cast bullets could be a very tangible reality. It's real hard to pull the trigger on a deer a long ways off, if the consistency of your load is balanced on the tip of a needle, but these results of yours show very consistent and usable hunting accuracy (even the "sub standard" ones).
Very exciting!

[Bjornb]

Range trip again Sunday. After a surprising cold snap (below 40), it was warming up nicely.
Due to a marathon fire forming session for my XCB rifle (340 cases) that I described over on the HV thread, I had been struggling with some serious barrel leading (even though I was bragging at the time that there was NO leading), and not until Larry advised me to shoot a few backwards seated jacketed bullets (.311 dia.) did I get a handle on the leading problem. 2 range trips with cr@ppy groups were wasted, and I even thought there was a shooter problem!:oops:

Here are some sample groups with known accurate loads and a barrel full of lead:
131931

Anyway, I needed to get my confidence back, and I loaded up some strings with both old and new cases (not mixed), to see if they would perform differently. I had formed the second batch very differently that the first; the newer brass had been fire formed with undersize bullets with the goal being to get the necks ironed out completely (without the shade of the old 30-06 shoulder) before being turned.
After shooting 10 rounds with a moderate load, to condition the clean barrel (White Label 2700+ lube and NOE 165 XCB bullets were used), I shot these 2 groups:
131932131933

I was happy with the results, since it showed that the leading was most likely all gone.

Finally I shot 3 strings with jacketed, again to see if the new brass would behave much differently from the old.
131934131935131936

Yep, I threw 2 out of 30. I am mostly posting these groups as a shameless plug for my good friend Tim Malcolm AKA Goodsteel, who builds insanely accurate rifles and is also one hell of a good guy.

It was a good day at the range.

[Hannibal]

Tim Malcolm AKA Goodsteel, who builds insanely accurate rifles and is also one hell of a good guy.

It was a good day at the range.

VERY nicely done, Sir! And I couldn't agree more.

[Nrut]

+2
Those are amazing 10 shot groups!

[35 shooter]

Super nice at those speeds with cast. Right on time too as i was going to pick up some 760 to try in my whelen or h414. I've kept up with a lot of this but i know i've missed some of what's been tried. Have you tried the h414 in your rifle? Some say they are the same powder but i used to have both on hand and seem to remember a difference in appearance? Seemed like the 760 was darker so it may just be a difference in coating or i may not be remembering it right....been a few years. Glad you got the leading thing figured out....things like that can run you nuts till you find out for sure what's going on. Hoping i can ease the speed up a bit with one of those powders in my 1/14 twist whelen. Again very good shooting!!

[Love Life]

That's how Tim's rifles shoot.

[Bjornb]

This was the last of my W760 and I picked up some H414 recently. I poured them into 2 plastic cups and compared them side by side. Visually I could detect no difference.

[MBTcustom]

Excellent shooting Bjorn. That really is a fantastic rifle.
Thank you all for the kind words!

[cainttype]

Good post, Bjornb. The minor leading issue and post-cleaning groups clearly demonstrate a common problem that might be easily overlooked when pushing the limits of any load combination... I have more than a few toys I might have bragged on with 3 MOA groups at over 2800 fps with cast! lol

Although I'm generally well served with much less speed using cast, I have toyed with breathing new life into a hunter-benchrest type rifle that hasn't seen use in years. It's chambered in 308x48 and twisted 1-14.
I have considered rechambering it's 24" barrel to 308 Win in the past. I have a sporter style stock in hand and would lean towards fluting the barrel for a little weight reduction... Not there, yet, but thinking about it more often.

[runfiverun]

I thought groups like that come from pulling the trigger then trying to see the boolits fly through the air in the spotting scope. :kidding:

[Bjornb]

I thought groups like that come from pulling the trigger then trying to see the boolits fly through the air in the spotting scope. :kidding:

With the Weaver T36 scope no spotter is needed!:target_smiley::target_smiley:

[Larry Gibson]

The information I give in post #16 in http://castboolits.gunloads.com/showthread.php?95248-Borderline-Stabilization-at-long-range is still correct and applicable to why several of us have migrated to 14 and 16" twists with more such longer barreled slower twist rifles being built. The results from shooting these with cast bullets at 2600 - 2900+ fps while maintaining 1.5 moa and less speaks for itself.

Obviously the information in the Accurate Bulletin demonstrates that the effects of RPM is an important consideration. Most of the ballistic world understands this. What being actually demonstrated in this thread documents that understanding.

Larry Gibson

[Outpost75]

Most of John Ardito's CBA records were fired in .308x1.5" with 200 grain bullet seated out and held by the GC only, with a caseful of RL7, using 14" twist Hart barrels on a sleeved 40XB action. Bullets were tapered in a bump die cut with the same throater used to do the barrel. He used monotype alloy and the old RCBS green lube, sequentially reloading the same case over and over again, no sizing the brass, just decapping, cleaning the primer pocket, repriming, filling the case full of powder in a rice bowl, striking it off with a card, starting the bullet with his fingers and seating it about 1/8" into the case using a Wilson type seater in an arbor press. Mold was one he cut himself which resembled 311299 before bumping.

[Love Life]

Off topic alert!

For those who have been running cast full tilt, have you hade the barrels scoped? Is throat erosion similar to running full tilt jacketed?

[MBTcustom]

Off topic alert!

For those who have been running cast full tilt, have you hade the barrels scoped? Is throat erosion similar to running full tilt jacketed?

No barrel has returned to the shop for inspection yet, except the original barrel on BjornBs Bertha rifle.
Bjorn can give a figure on how many shots had gone through that barrel.

I did take the opportunity to scope that barrel before borrowing it to build the Felix rifle, and the wear at that point was minimal. Had I seen this barrel unaware, and assuming it had been shot only with jacketed, I would have assumed it had less than 100 rounds through it.
The fine tooling marks left by the reamer were wiped out and the edges of the rifling in the throat were smooth like the rest of the barrel.
No flame scoring (this happens rather quickly with jacketed and looks like fine scratches extending from the chamber to the end of the throat.)
No gator belly at all.
It looked smooth and clean.
Thats all the help I can give at this time.

[Love Life]

Thanks, Tim!! I am very much interested in throat wear and overall barrel life running full tilt cast as you all are doing. If you recall, my slow powder, low-ish pressure, experiment with jacketed IRT barrel life did not turn out as I expected.

Back on topic now!

[Larry Gibson]

Love Life

I am planning on only using "full tilt" cast bullet loads in Dawn, my 30x60. I am recording every shot through the barrel. I should have a very good idea of the accuracy life of the barrel. I don't have a bore scope but am measuring the throat for erosion.

Larry Gibson

[MBTcustom]

Thanks, Tim!! I am very much interested in throat wear and overall barrel life running full tilt cast as you all are doing. If you recall, my slow powder, low-ish pressure, experiment with jacketed IRT barrel life did not turn out as I expected.

Back on topic now!

I'm all over it LL. As soon as I get a barrel back, I'll scope it out.
However, I once had a conversation with Larry Gibson and he had some experience in that regard that he may share here.

All I know is that not one single person has sent me back a barrel for a setback, and I've been doing this for a number of years at this point.

Remember the recipe for a burnout:
Fast twist
heavy bullets
Slow powder
Overbore cartridge
High pressure

As cast bullet shooters, with the 30XCB we only meet one of those criteria because nearly all of them would be detrimental to accuracy with cast lead. Also, it's not the bullet composition/hardness that burns out the barrel, it's the chemical reaction under pressure that does it. Therefore, I would speculate that if the burnout rate is identical for cast vs. jacketed, based on pressure, bullet weight, twist rate, and cartridge design, it would take about 6000 rounds before any measurable negative effect could even be detected, and we are a long way from seeing that from any of the shooters here.
Near as I can tell, the average cast bullet shooter involved in these projects shoots about 1500 rounds per year if he's really ambitious. Ie: get comfortable because this could take a while!
The average 308 requires about 3000-4000 rounds to burn it out with pressure in the 50,000psi range and a 1-10 twist rate. (That's match grade accuracy where your .5MOA turns into 1MOA). So reduce the pressure, slow the twist rate, use a softer bullet that generates less back pressure, and open your accuracy requirements to 1-2 MOA, and your barrel life is looking really really good for a long period of time.
I'm hoping to get the chance to scope one of these barrels after several thousand shots have been fired, but given the above prediction, lets just say I'm not holding my breath.

[Larry Gibson]

popper

Wondering where you got those "stability factors"? What formula was used?

Larry Gibson

[Larry Gibson]

Here’s what 3000+ fpslooks like:bigsmyl2:

The original accuracy/velocity criteria for the 16” twist with the 30 XCB bullet was 2 moa or less 10 shot groups at 100 yards at 2800 – 2900+ fps while maintaining linear dispersion to 300 yards. With my 30x60 XCB rifle, Dawn, objective criteria was met within the first 100 rounds tested. It was observed that the 30x60 cartridge in Dawn might be capable of 3100+ fps and maintain accuracy.

However, since it was taking a measured (Oehler M43 PBL) 48,000 – 52,000 psi to accomplish that thequestion that comes up is; will #2 or linotype alloy hold up to that pressure and acceleration? Initial testing with 3 difference powders resulted in poor accuracy although the 3100 fps goal was attained. As I previously reported the problem was some of the GCs were coming off the bullet immediately on muzzle exit. No doubt about this exists as the heavily damaged chronograph screens give adequate testimony.

It was a given if we pushed the ternary alloyed cast bullet hard enough and fast enough plastization of the bullet would begin. Plastization (the alloy begins to get soft transforming from a solid to a semi solid state) is caused by pressure and heat. The place where the pressure is highest and probably where the largest heat transfer occurs is the base of the bullet…..exactly where the GC is. If the base of the bullet plasticizes then the GC crimp has nothing to hold onto and would readily come off. It was believed this was what was happening in the 2950 fps+ velocity. I’ve been working on solving a problem the last several weeks but realized that at some point the ternary alloyed cast bullet could be pushed only so hard and maintain accuracy.

One of the 1stthings noted with the use of linotype alloy was the very good fill out and minimal shrinkage. The linotype bullets drop outof the NOE 30 XCB mould just a tudge (only a couple ten thousandths) under .311which is about .0005 - .0008 larger than with #2 alloy. This meant the GC shank also was a bit larger in diameter. Noting that when the Hornady GCs were seated using a .311 H&I die and the Lyman GC seater in a 450 Lubrasizer the crimping portion of the GC was scraping part of the shank forward. To correct this goodsteel made me one of his GC uniforming tools with swaged the Hornady GC to a proper slip fit over the GC shank. The uniformed GCs then were a perfect fit on the 30 XCB bullets.

I had recently cast some 30 XCBs (about 5 days ago) and since they were WQ’d they were ready for use. I weight sorted them into .1 gr variation lots (see my post on that in the Consistency Thread). I selected some of the sorted bullets of equal weight and GC’d them with the uniformed GCs. They were then sized and lubed (Lars 2500+)in the 311 H&I die. I honed a Lee.309 push through sizer to size the linotype 30 XCBs at .310 to fit the throat diameter of the 30x60 chamber throat.

A previous test with LeveRevolution powder showed 3000 – 3100 fps with 49 and 50 gr. The pressure was 51,000 and 56,700psi(M43). Accuracy was poor due to the GCs coming off as evidences by a 5.3 and 8.4” ten shot groups. The velocity for the 49 gr load was 3025 fps and for the 50 gr load it was 3103 fps.

Last night I loaded 10 shot test strings of 49, 49.5 and 50 gr LvR. A 1/3 gr Dacron filler was used. The .310 sized linotype alloy 30 XCB s were loaded.

I was able to slip off to the range today around noon. It was a paltry 80 degrees with a mild 2 -3 mph wind coming out of 6 o’clock. I fired 2 foulers into the berm and then fired the 3 ten shot test strings back to back. I let the barrel cool about 2 minutes between shots. I did not set up the M43 or the M35P chronographs as I already had the data from 49 and 50 gr loads tested previously. My estimated velocities are based on that previous test.

The 1st groupwas the 49 gr load which went into 1.65”. That should have been close to or just above 3000 fps. The diamond measures .75 on a side.

134528

The next ten shot was with 49.5 gr and it went into a very nice and consistent 1.25” group. The velocity should be around 3050 fps for that load. Now that's what we're looking for:bigsmyl2:

134529

The last group did not fare well and it was obvious the GCs of several of the bullets were shed and the bullets were unbalanced. The velocity should have been about 3100 fps. As we see here it doesn’t matter how well we make and load the bullets if we push them too hard. It is how balanced they come out the barrel that matters. In this case the bullets were unbalanced and the loss of accuracy shows that. As ballisticians such as Rinker and Litz note the unbalanced bullet is adversely affected in flight by the centrifugal force created by the RPM. Here we find, at 3100fps the RPM to be 139,500…….right at the top end of the RPM Threshold…..fathom that.

134530

I would say that right about 3100 fps is about as far as we can push a ternary alloyed .30 caliber bullet. At that velocity and pressure it is obvious some pretty bad things happen to the bullet during acceleration. That means no matter how perfect we get the bullet into the barrel it's just not going to come out perfect (as in balanced) and it crosses the RPM threshold and accuracy goes south. At this point in my testing I will see what the 49.5 gr load can do out at longer range, perhaps to 600 yards. I then will do some testing with the breach seating tool goodsteel made for Dawn. Perhaps with breach seated bullets we can push above 3100 fps before crossing the RPM threshold....given the experience Bjorn had with his 14" twist Bertha in 30x57 XCB more could be possible in the 16" twist of Dawn with the 30x60 XCB. We shall see, the experimenting and testing continues.

Larry Gibson

[Hannibal]

(Insert the sound of a low, long whistle).

THAT'S going to be a tough act to follow! Thank you for sharing, Larry. And well done Sir!

[MBTcustom]

That's firmly breaking 3050FPS with fixed ammo, and a standard cast bullet with pictures, load data and a demonstration of progress to boot, but only two months after I shipped the rifle.

Larry, we are lucky to have your input on this forum. In the quest for HV, post #167 on this thread is the best that has ever been posted in this forum IMHO, and bravo to you for sticking to it and making it happen, just as you said you would.

You accepted a rifle build for free, but paid me after the fact.
You claimed 2" groups but you shot 1.5
You claimed 2800fps, but shot 3000.
You theorized that RPM is the biggest limiter of HV shooting with cast, but you paid the price to demontrate and prove in here in open forum.

In short, your actions speak louder than any words you will or have typed on this forum.
Thank you sir!!!!

[mnewcomb59]

I've gotta say, I personally believe that RPM can be interchanged with stability factor. Stability factor is a calculation that gives you a number you hope is near 1.5.

1.5 is the bare minimum gyroscopic stability needed to keep a projectile of a given length, weight and caliber from tumbling.

Less than 1.5 means the bullet will yaw. It may shoot decent for a certain distance, then after that distance groups will open up non-linearly.

Anything over 1.5 means your bullet has more RPM than it needs. When a bullet is way over spun, it will not go to sleep after its apex and start falling point first like a good football toss. Instead, it will maintain its same angle it was launched on (point slightly up) , eventually showing up as oval holes at long range.

Pretty much if you have any choice, pick your heaviest bullet weight you will shoot, figure out what twist length gives around 1.5-1.8 stability factor, then try to find a rifle with that twist.

As bullet weight goes higher and higher for caliber, lead bullets will struggle. First of all, they will need a faster twist, which is harder on the driving bands. Second, the first driving band of your 1.5 inch long 240 grain 30 caliber bullet will have to bite and torque the whole long, heavy bullet. In reality, the first driving band would probably skid, causing deformation and loss in accuracy even if the gas check caught the leading.

I think people trying to get 3000 fps+ would be better served by experimenting with low to middle sectional density bullets. The first driving band can easily bite and torque a 125 grain 30 cal into rotation compared to the front driving band on a 30 cal biting and torquing a 240 grain, for example.

Here are my personal results in my slow 30" twist 357 Rossi rifle. This gun is giving me really good accuracy (1 MOA) between 1800 and 2100 fps plain base. I sort bullets for good bases and tumble lube. 17.4 Lil Gun is also MOA, and the 18.6 grain (Brian Pearce data) load shows promise. I bet the vertical stringing was because my scout scope and eyeball alignment. Can't wait to do some shooting this spring. I hope to find the 18.6 grain (2000 fps) load just as accurate as 16 and 17.4
134553

I would have shoot lead at 3000 fps in this 30" twist to have the same RPM (driving band torque stress) as a 10" twist 9mm at 1000 fps. What does this tell you about 9mm needing harder lead? It has enough twist for subsonic Whelen bullets! This 30" twist at 2000 fps is putting less stress on the driving bands than a 16" twist Ruger Blackhawk at 1100 fps. This 30" twist is so slow that the driving bands hold tight while the lube groove deforms and pumps.

One time I shot some 9 BHN Lee 125-RF at 2100 fps and recovered some bullets. The twist rate is so slow that there was no skidding on the driving bands, but the lube groove was completely swaged out. Also, the bases cupped really deep from the pressure. Accuracy went down to 3-4 MOA, and I suspect off center sprues and the deep base cupping threw off accuracy. No lead in the barrel with that soft alloy at around 2100 fps.

[cainttype]

Thanks for an excellent field report, Larry. I'm looking forward to the extended range testing results.
I'm still kicking around devoting a HBR rifle to cast-only, but I lean towards rechambering to a match 308 Win.. The chamber neck is much tighter than I'm interested in having for the project in it's current 308x48 configuration, but I want to at least run it through some preliminary testing before any final decision is made.
Now... If only I had more time... retirement sounds really great, right about now.

So, Mike... What is the status on your new lead-slinger project?

[swheeler]

Very good Larry! I would say you exceeded your own expectations with DAWN, what's not to love;-) Another 1k of those loads and you can start chasing the rifling and will have a base for answers as to throat erosion some have asked. To go where no one has gone before, you should have been an astronut:-)

[Larry Gibson]

Mike

My retirement goal is to wear out most all of my firearms! I'm working hard at it. I have no idea how I ever found the time to actual work before I retired. Retirement is a full time job!

Larry Gibson

[Larry Gibson]

Cainttype

All of my 10, 12 and 14" twist HV load development was done with the .308W. The 30x57 has basically the same capacity as the .308W but has the longer '06/30-30 neck. The 30x57 is a wildcat and Tim chambers it using very tight specs, especially the neck and throat designed for the 30 XCB bullet). It is not a difficult case to make. However the .308W with a match chamber and tight neck in a 26"+ length barrel with a 14" twist will also do nicely. Might have to throat it a bit so the GC doesn't get below the case neck though but I've not had to do that with the 5 different .308W/7.62 NATO chambers I've used the 30 XCB in. I've had very good results in the 2600 - 2700 fps range in my .308W Palma rifle with 27.6" barrel with a 14" twist.

Larry Gibson

[cainttype]

Larry, I'm going to have to wring out the 24" tube (1-14" twist) the rifle has before rebarrelling is a serious propostion. If it behaves well, as is (I think it will), I may opt for the 308 chamber to get rid of some case forming issues for convenience.
The short action Rem 700 action limits choices, but I've considered incorporating a longer neck (similar to the 30x57) in the existing chamber. It's currently nothing more than a 308 Win reamer short-chambered by 3mm, so adding almost 1/8" of neck is a definite possibility.
I have to admit that if the rifle shoots any cast nearly as well as jacketed, I'll be pretty happy. I'm not anticipating anything near the speeds you are accurately achieving with "Dawn", but I will eventually find my limitations with the smaller case capacity...In good time. :)

[1johnlb]

Well, I decided to join in on the slow twist chase for speed. I've picked up a new stock and a shilen 1in14", 30" long in 308 win to fit my savage 10fp. I'm still in the fire forming stage but just wanted to post some of my results.

I obviously tried to begin with the 30 xcb but had fit problems that set it way deeper than I would like, so I tried some of Larry Gibson ' s loads with them and the Lee 155 ' s and the NOE 129 sp on the first 100 cases of winchester brass with nothing special to write about. At this point I went through my 30 cal designs to find a better fit for fire forming the next 100 cases of PMC. I decided to try the lyman 311299 next because it fit the bore of the muzzle perfect and seated perfectly in the case when touching the lands. The 299s were originally tumble lubed and gc ' ed with Hornady checks cast from 2 parts ww and 1 part monotype, sized at 311 and later on pan lubed with 2500+. Before loading I weight sorted then loaded starting with h4831sc and accurate 4350. S&B standard primers. Shot at 115 yds.

While I know that I'm setting no speed records with the 299s but believe that I will be able to push the upper limits of a 200 gr projectile with good accuracy. This to date is my most accurate cast groups and when all is fully refined, I hope to see if it holds out to 200 meters and repeatable.

134635
All the 4831sc loads left unburned powder with about 90 to 95% case fill.

134636
I had 2 called flyers with the 41 gr load, the bulls eye hit was the first were I set the trigger to early. Throwing them and the cold barrel yielded me a .6 even group. Wow that's my best cast group, ever. The barrel ran remarkably cool with the 4831, never more than just warm to the touch.

134637
I had 1 pulled flyer and 2 rounds from a cold barrel. The 6th shot cold barrel was from being distracted.

134638
Here's a pic of the new girl in town, ain't she purdy. Now to go push em a little harder. I'll post velocities when my chrony comes in, still waiting on the funds.

[Larry Gibson]

1johnlb

As I mentioned to cainttype some .308Ws are to short throated for the 30 XCB bullet with the GC being seated below the case neck. The shortest throated .308E chamber of the 5 I have allows the top of the GC to be right at the case neck/shoulder junction. That hasn't caused any problems. If your rifle's throat is shorter then a touch with a throating reamer would solve the problem. The 30 XCB is designed for the longer '06/30-30 neck and it optimizes bullet weight with bearing surface and no bore riding nose. It is the best design if you want to optimize your barrels capability upwards of 2600 - 2700 fps.

Some pundits have continually complained the slower 14" twist isn't useable with "heavier" cast bullets. Not only have I proved them incorrect numerous times but now you are to with the 311299! I was able to push my own 311299 upwards of 2400 fps in my 14" twist .308W Palma rifle. After that as you push the bullet harder the minimal bearing surface, large lube groove and long bore riding nose work against maintaining accuracy.

Well done BTW!

Larry Gibson

[1johnlb]

Thanks Larry, if I can get any were close to 2400 I'll be happy. But then I'm happy with those groups regardless. If those will hold moa out to 200, I'll be even happier.

I wasn't very clear before and didn't give the xcb, Lee 155, and NOE 129 a good start by weight sorting any of those and what I experienced was very likely due to that fact. I haven't given up on any of them.

My 30 xcb seated at 2.53 oal, which put the check at the shoulder/ body junction. I'm not likely to change the throat, shooting the 299 that well. I also have a Savage 110 long action that I'm considering putting a Hart's barrel on. At this point I'm thinking about letting Tim chamber it for the /06 and ream it for the xcb, but unsure for the moment of what twist. I'll be watching closely for more post from you and others on the progress of the slow twist.

Thanks again Larry and all those taking the time to share their experiences and wisdom on all the accuracy techniques. I for one have learned more on these recent threads than I ever knew.

[dtknowles]

Larry, nice work. Thanks for sharing.

Tim

[tomme boy]

1john. Goodsteel has a copy of the print that Shilen uses for the 308W. We got it to check over my barrel for me. Might want to PM him to help find out what size to use for your bullets.

I have over 3500 rounds of cast through my Shilen 1-10 twist. And I am still able to hold less than 0.5" groups with 168gr Hornady AMAX bullets. I have over 600 rounds of Jacketed through the barrel on top of what I have shot cast also. So that might give some a clue as to how long the barrels will last.

Tim can say as to what it looked like. As he scoped it. Tim???

[Larry Gibson]

As I said in my last post on the results from the 30x60 using the 16" twist rifle Dawn, the next step would be to conduct a longer range test of the 49.5 gr LeveRevolution load to test for linear group dispersion. I conducted that test this morning at 200 and 300 yards. The load was the same; 49.5 gr LvR with a Dacron filler (1/3 gr). The bullet was the 30 XCB cast of linotype and WQ'd. Velocity runs right at 3000 fps with the linotype bullet sized at .310 and lubed with 2500+.

Looking at the 100 yard groups of 49 and 49.5 gr LvR I shot the other day and posted in the last report we see basically 1.4 - 1.5 moa between the two of them.

134931134932

Thus for linear expansion/dispersion of the groups at 200 and 300 yards we should expect about the same moa of 1.4 - 1.5. I was hoping to beat the wind this morning but it was not to be. There was a blustering non consistent 4 - 8 mph wind coming from 1 - 2 o'clock. Knowing the wind would only get worse I shot the 300 yard target first. The 10 shot group was 4.5" even with the wind. That is 1.5 moa.

134933

I then put a target at 200 yards and measured the wind.......it was still coming out of 1 - 2 o'clock but had picked up running from 7 - 10 and gusting to 12 mph. It also would just die momentarily. I shot the 10 shots trying to gues when the wind was consistent but with no real wind indicators other than the feel of it at the bench I didn't do to well. That nice 5 shot group to the right is the result of the wind dying just as I pulled the trigger! None the less the over all group is right at 3" for again, 1.5 moa. There is an eleventh shot in there for you bean counters; I took 3 foulers with me and fired 2 before the test. I decided to shoot the last fouler into the 200 yard group. It is the high left shot of that five shot group on the right from when the wind died.

134934

This test demonstrated the linear group expansion/dispersion is consistent at 1.5 moa for 100, 200 and 300 yards. That is exactly what we were looking for. This is an excellent load and will probably be my go to HV load for Dawn. I will be further testing this load at 400 - 600 yards in the near future. However, I have one other Powder to test with the linotype 30 XCBs. The testing continues but the RPM Threshold is well proven. What is also well proven is how to shoot real HV with cast bullets accurately if that is your goal.

Larry Gibson

[Yodogsandman]

Outstanding! Thanks for sharing your every step and your reasoning behind it!

[cainttype]

Larry, thanks for the update. It's more than just a little bit interesting to watch the results of the efforts, time, and money that all of you gentlemen have invested to put your ideas into practice in order to test them in this spectrum of slinging lead downrange.
Hopefully your results with "Dawn" won't discourage others from posting any results they achieve with rebarrels and/or rebores while experimenting to find the HV potential of their own combos...Let's face it, 3000fps while maining linear accuracy to 300 yds is a pretty hard act to follow. :)
Mike (IIRC) commented awhile back that his definition of HV with cast would be matching factory jacketed speeds...seems reasonable enough for mid-sized cartridges in medium-to-large bore diameters, especially now.
I've never felt the need to pursue velocities that high, having always been happy with speeds that ranged from the mid-teens to 2500fps. The work you have all been doing has given rise to an new interest in higher speeds that has me thinking... so it is entirely possible that I'll put the blame on all of you in the future.

[MBTcustom]

Outstanding results Larry. There is no better reward a craftsman can receive than to see the things he has made being used for the purpose they were intended to serve.

Cainttype: I don't know why people would be discouraged? In the past HV cast shooting has been a dark art that can only be taught by people who can't teach, and can only be learned by those who can't learn. Larry has been trying to tell people how to cut to the chase for years, and has demonstrated how to do just that. If someone wants to do as he has done, but pick and choose what parts they want to listen to, then they certainly will get discouraged very quickly.
However, if they follow basic techniques for loading precision ammo, use excellent alloy, and use the correct twist barrel, it's pretty much plug and play.

I would like to illustrate my point with the fact that I have a shipping ticket here with a date of 1-21-15. That was the date I dropped this rifle in the mail to Larry Gibson. It was a new wildcat cartridge (longer than the 30XCB) and the entire rifle was gone through in my shop. The action was trued, new hinged bottom metal was installed, a brand new barrel was installed, and when he received the rifle, the bedding was redone. For all intents and purposes, Larry started a month and a half ago with a brand new rifle that he had never shot before!!!! That makes a pretty big statement all by itself.

I think more results will be forthcoming this year. I just took in a shipment of slow twist matchgrade barrels today, and I think that at least some of them will be showing up in this thread, or on castboolits. Very interesting times lay ahead!

[cainttype]

Tim, perhaps I wasn't clear.
I meant to welcome everyone experimenting with these non-factory barrels to post their results. I was trying to clarlfy that results with any caliber, and the "HV" trials, others may be engaged in testing would be welcome here.
Obviously there will be interesting experiments resulting in less than 3000 fps, so there's no need to worry if your pet project is not in that realm... The pursuit of matching factory speeds is challenge enough. How you get there is all the fun.
As I have admitted before, anything in the 2500fps range has been HV in my world...That view is changing, although I still spend most of my time with loads in the mid-teens to lower 2000+ range. Using mostly hunting weight rifles, that's often all I'm willing to spend an afternoon pushing lead through.
I believe you are correct, "Very interesting times lay ahead!". :)

[MBTcustom]

134946
hmmmm ....... Look anything like this???

Hmmmm, must have had a trunk monkey with a camera behind me. LOL!

[MBTcustom]

Tim, perhaps I wasn't clear.
I meant to welcome everyone experimenting with these non-factory barrels to post their results. I was trying to clarlfy that results with any caliber, and the "HV" trials, others may be engaged in testing would be welcome here.
Obviously there will be interesting experiments resulting in less than 3000 fps, so there's no need to worry if your pet project is not in that realm... The pursuit of matching factory speeds is challenge enough. How you get there is all the fun.
As I have admitted before, anything in the 2500fps range has been HV in my world...That view is changing, although I still spend most of my time with loads in the mid-teens to lower 2000+ range. Using mostly hunting weight rifles, that's often all I'm willing to spend an afternoon pushing lead through.
I believe you are correct, "Very interesting times lay ahead!". :)

I really wasn't arguing with anything you said, just wondered why any of this would be discouraging to anyone. This is the clearest path to HV shooting with the most solid results that has ever been posted. I find that to be beyond encouraging!


Larry has put himself in the drivers seat and showed us how to drift. If he can do it, then anyone can do it. It's all been explained very clearly.

Three years ago, I heard tell here on castboolits of how some people claimed to be able to shoot HV with cast, but the path to fruition was like walking through a swamp with wet matches to light the way. I decided I was going to do whatever it took to encourage all the players to shed light on their method and demonstrate it clearly so that others could follow their path. First there was paper patching, and geargnasher footed the bill perfectly with his clear demonstration with the 270 Winchester. Now we have a naked cast bullet matching and surpassing those speeds.
It has been expensive, time consuming, heartbreaking, I have lost more sleep over this issue than I care to admit to, and I have given everything I can possibly give to help anyone who so much as mutters under their breath a claim of HV with accuracy (in fact, you could probably squat the springs in my truck with all the custom rifles, molds, dies, and reloading equipment I have sent to the key players) but the results are worth every bit of it, and now castboolits is the best place on the internet (dare I say in the world) to learn how to do this.
So far, all the evidence shows that slow twist barrels and paper patching seem to be the best ways to get to HV with cast, and thanks to the hard work of forum members like Larry Gibson and Bjornb, we now have a very clearly laid path to that goal for anyone who cares to pursue it.
I'm elated by the progress that has been made by those who have taken the time, and had the courage to demonstrate their claims. The science has cut through the superstition, and the groups tell the tale.
Bravo!

[tomme boy]

Tim, what make of the blanks?

[1johnlb]

sgt.mike


Attachment 134946
hmmmm ....... Look anything like this???


Are they spoken for? Or up for sale

[1johnlb]

Yes, brux quoted me 6 months. Can't blame me trying can you?

[Hannibal]

There is a 'surprise' or 2 in that bunch if I am not mistaken. THOSE are the ones I'm anxious to see on the range.

[Eutectic]

I've got an old Savage Model 342 that I bought over 50 years ago. For $35 !! It was my first varmint rifle and my first Hornet. I have always been teased unmercifully about how ugly it is! But it never took a backseat in the accuracy department! It has sat in the dark for over 30 years. But recently I brought it out again.... mounted a scope and have shot cast in it. It's still accurate!!

I've got a new lube formula. Not a spin off of anyone else's lube formula either. It has common components; just arranged different. All I'll say for now as this isn't the Lube Thread.!! And I'll test before I talk details. But I used it in the 'old Hornet' yesterday and today..... Why??

The lightning fast butter soft alloy load I used is a real 'lube tester'! If you can get 10 rounds through the barrel with speed and soft alloy together you have a tough lube! Reason I used this new formula. If it can't take it then it can take a leave.

I fired half a dozen plinkers fouling the clean bore of my old Savage yesterday. I kept four for this morning...

This ol' gun cold starts about 1 to 1 1/4" high with boring regularity but dependable to do it with several lubes. Mike's 666-1 cold starts under an inch.

So this morning I tried the lightning fast butter soft alloy load in my ol' girl...The NOE 225107 cast from 8.5 bhn alloy weighs 38 grs. hollow pointed .058" x 185" deep. I shot over the chronograph as well as the Model 342 has a short barrel.

The group is attached ... 85 yds. Cold start is the higher one. Next three were in a hair over 7/16"! Even with the cold start included it was a hair under 7/8"....... They chronographed 2823 fps...

Eutectic
135196

[Larry Gibson]

Amazing what can be done with slower twists for sure.

Larry Gibson

[NC_JEFF]

As a very interested novice at shooting cast accurately in the rifle I have, do the paper patch guys use slower twist barrels or "standard" twist for caliber barrels? Or both?

[detox]

Larry, Have you tried softer alloys with your slow twist barrel? Maybe it will work?


BTW....I really like the looks of this rifle. Notice the barrel is clamped to stock. Much like a test barrel in a balistics lab. Is the receiver floated also?

[MBTcustom]

Larry, Have you tried softer alloys with your slow twist barrel? Maybe it will work?


BTW....I really like the looks of this rifle. Notice the barrel is clamped to stock. Much like a test barrel in a balistics lab. Is the receiver floated also?

Yes, the receiver floats from the block to the stock, the barrel floats in it's channel, and the scope rail floats over the action.
When I was building the rifle for Btroj, I offered to build him just such a rifle as you show in the picture but he declined.

[MBTcustom]

As a very interested novice at shooting cast accurately in the rifle I have, do the paper patch guys use slower twist barrels or "standard" twist for caliber barrels? Or both?
The easy answer is: Both
Jacketed bullets usually shoot best when they are spun just fast enough to stabilize at the maximum distance you shoot. Therefore, a discerning target shooter will choose a twist that stabilizes his bullet just far enough for it to punch a hole in the paper he is shooting.
That said, jacketed bullets allow the core to slip, this preventing damage so it is possible to over spin the living hell out of them, which makes them perfectly suited to factory twist rates, (although perhaps not really ideal for the 100 yard range).

[Larry Gibson]

Yes I have tried softer alloys. No they do not hold up to the velocities and pressures that #2 alloy and linotype stand up to. They simply can not withstand the higher acceleration. Earlier in this thread I posted results of two bullets of two softer alloys. You can readily see where they crossed the RPM Threshold and that they didn't give the best accuracy above 2400 fps.

Larry Gibson

[A pause for the COZ]

Wow!!! Bravo!!!
I caught this thread late and was amazed at what I have seen.
We are fortunate to have guys that can put in the hard work.
I do notice I have allot to learn.

I have noticed similar results but coming from a different end. Trying to get 223 cast bullets to shoot out of my 1-9 twist AR carbine.
kind of got it to work using a heavier bullet 75gr and keeping them in the normal speed range 1700fps or so.

Finally gave in and built a 1-12 rifle. Its a completely different animal.
I have 65gr boolits shooting good with out working too hard at all. And pushing them fast too.
I ummmm shot my Crony so I haven't tested them yet. But I bet they are zipping along in the 2500+ range.
Point is, just slowing the twist took an effort in hair pulling and made it a fun process.

Keep up the good work and I will keep reading it....

[MBTcustom]

Wow!!! Bravo!!!
I caught this thread late and was amazed at what I have seen.
We are fortunate to have guys that can put in the hard work.
I do notice I have allot to learn.

I have noticed similar results but coming from a different end. Trying to get 223 cast bullets to shoot out of my 1-9 twist AR carbine.
kind of got it to work using a heavier bullet 75gr and keeping them in the normal speed range 1700fps or so.

Finally gave in and built a 1-12 rifle. Its a completely different animal.
I have 65gr boolits shooting good with out working too hard at all. And pushing them fast too.
I ummmm shot my Crony so I haven't tested them yet. But I bet they are zipping along in the 2500+ range.
Point is, just slowing the twist took an effort in hair pulling and made it a fun process.

Keep up the good work and I will keep reading it....

If you'd gone with a 14 twist, you'd have been in the 2700FPS range, and if you'd gone with a 16 twist you'd be in the 3000FPS range.
If you haven't already, this is a good read on the subject: http://castboolits.gunloads.com/showthread.php?208186-RPM-Threshold-barrel-twist-velocity-chart

[Hannibal]

hehe ok Darrin don't let the cat out yet... LMAO it might pee on your leg again (sorry could not resist that one after that text you sent).

But yes once the build is complete there will be some details covered by the builder (Goodsteel, even though I have not discussed this with him) that Expanman is alluding to.

Hey, it's all good! If a man can't laught at his mistakes then he's taking himself much too seriously, eh? LOL!

[detox]

Yes, the receiver floats from the block to the stock, the barrel floats in it's channel, and the scope rail floats over the action.
When I was building the rifle for Btroj, I offered to build him just such a rifle as you show in the picture but he declined.

The block/clamp would allow quick easy barrel /recoil lug/receiver change. Stiff scope rail is attached to top of block or receiver. Clamp/block is bedded and bolted to a stiff laminated wood stock. Both the barrel and receiver are free floated.

Goodsteel, Could you make and sell one of these barrel clamps. A simple V shape could be cut as channel to hold different barrel diameters.

[MBTcustom]

The block/clamp would allow quick easy barrel /recoil lug/receiver change. Stiff scope rail is attached to top of block or receiver. Clamp/block is bedded and bolted to a stiff laminated wood stock. Both the barrel and receiver are free floated.

Goodsteel, Could you make and sell one of these barrel clamps. A simple V shape could be cut as channel to hold different barrel diameters.

I certainly can and have.
But it's very dependent on stock design as to how deep, wide and long to make the block.
Also, I do not recommend making it a V bottom. Unlike a bedding block for the action, the barrel has no recoil lug to stop on the block, so you are entirely dependent on surface contact to keep the barrel from being driven back through the block. Also, you have to figure that you don't want to be applying three points of pressure in the barrel as it undergoes the stress of firing. The block works more by having a lot of contact 360 degrees around the barrel like a collet.
In contrast, the bedding block for the action is supporting something that has no radial expansion at all, and I would submit to you that you are pulling the action down into the V block rather than smashing it between another piece of metal.
That's why if I build a barrel block, I do so by boring a hole straight through it to the diameter the client requires, while it is bolted together the way it will be used, with .005 shims between the blocks to set up a small amount of squeeze. If I were to venture a suggestion, I would recommend going 1.200 as all barrel makers can supply this dimension.

It's an interesting concept that certainly creates a very repeatable harmonic situation in the rifle if built and used correctly. The drawbacks are weight, and it requires custom profiles that are parallel for a good 4-6 inches forward of the tenon, and it's costly to build and install (but then again, all custom work is).

[detox]

I may contact you about this. Here is a quick drawing with recoil lug attached in regular fashion.

[MBTcustom]

The size and shape of the block looks pretty standard. The trick is inletting the block, action, and barrel, into the stock so that everything lines up correctly, and your trigger dangles through its slot in the correct location.
The holes for the action bolts must be drilled out and a threaded insert installed so that short screws can be used to hold your trigger gaurd/bottom metal in place securely.
The stock itself may need modification and/or an adjustable cheek piece installed because the scope is held a good 3/4" higher than usual (depending on design).
Just a few things that need to be understood about doing a custom build like this.
If you want to jump in there, PM me and we'll start hammering out a game plan.

[Bjornb]

Range trip today, after finishing a house build that took about a year longer than planned.

Not too happy with the results, and a little unsure about what caused the less than stellar results. I formed about 330 XCB cases a couple of months ago, and accuracy hasn't been what I hoped for with these cases. In addition, my previous go-to powder, Winchester 760, has been out of stock lately and I've been using H414, which is supposed to be the identical powder. I just don't know.......

Back in December i shot this group with W760:
136083
Then, in February, after forming new cases, I did a side by side test of old vs. new brass:
136087136088
Still not completely shabby, and velocity was good. This is a load that spins right at 140K RPM, and has been consistent in my XCB rifle.

So when the groups looked like this with loads from 41 to 45 grains of H414 I figured it was time to go back to the drawing board:
136089136090136091136092136093

I figured it's only fair that results less than stellar are also posted here on the forum; hopefully there will be improvements soon. I'm pulling the old brass down off the shelf, to see if the case batch has something to do with the poor accuracy.

The only positive development was the trial of IMR3031 in the XCB rifle; I shot a string of 12 shot with a load of 37 grains, aiming for about 2500 fps:
136095
This powder is definitely worthy of further testing.

Happy Easter, everyone!

[dtknowles]

Thanks for posting.

Tim

[1johnlb]

Well , haven't heard anything from the slow twist crowd in a week, so I'll post some of mine. The rain finally stopped and I was able to use my new chrony. I also came to the realization that my shooting bench has got to be mounted solidly, sitting on saw horses, just isn't stable enough for the higher recoiling rounds. By the time I got to the 7th group my groups were getting tighter just by loading the table.
I'm shooting the 308 shilen 1 in 14 twist with the Lee 312 155 sized at 309 with LARs 2500 lube. There was no lube star, the star on the muzzle was there but faint and dry. There was no leading in the barrel and my top velocities only reach 2600, far faster than any lead I've pushed before. I don't believe that the Lee 155 will be able to be driven much faster because of the lack of lube it carries.

136719

136720
136721
136723136727
136728136729

I've gotten more loaded but stopped here because of the bench, I will be starting over with the rounds already shot an sizing to 311, once I set some post in the ground.

[Bjornb]

That's really good shooting. I see you are using powders and charges that work really well in other 1-14 twist rifles, Larry's Palma rifle being the number one test bed in 308 Winchester. I'm not too familiar with the bullet you are shooting, but I would be surprised if lack of lube is a limitation. The NOE XCB bullet has 3 VERY shallow lube grooves and doesn't carry much. I bet that just refining what you're already doing (casting and case prep have both been hurdles for me) will tighten those groups just fine. Good job.

[Larry Gibson]

That's really good shooting. I see you are using powders and charges that work really well in other 1-14 twist rifles, Larry's Palma rifle being the number one test bed in 308 Winchester. I'm not too familiar with the bullet you are shooting, but I would be surprised if lack of lube is a limitation. The NOE XCB bullet has 3 VERY shallow lube grooves and doesn't carry much. I bet that just refining what you're already doing (casting and case prep have both been hurdles for me) will tighten those groups just fine. Good job.

I have to concur with Bjorn, the Lee bullet carries more than sufficient lube. At the higher velocities we also have higher pressures, both chamber and muzzle. With the higher muzzle pressures the lube star will be minimal because it gets blow away. I also have worked that Lee bullet at higher velocities in my own Palma .308W rifle with 14" twist and found it loses it about the same place you've found. I've surmised the two reasons are the long nose is unsupported with not enough bearing surface. The other is the deeper lube grooves create a smaller and weaker bullet column in the middle which can stand only so much acceleration. Those deficiencies were corrected in the design of the NOE 30 XCB bullet.

Obviously you've gone to some measure to have a slower twist rifle for shooting cast at higher velocities which is good. The problem is in the bullet design of the Lee. It is a fine bullet for its intended purpose but you built a Corvette and are holding it's performance back by using 2 ply tires on it intended for Chevette.....both "vettes" but quite a difference between them in performance level.


Picture is of my Palma muzzle after 100 shots pushing 2600 - 2700 fps; 1st 50 with XCB and 2nd 50 with 311466. You can see that even after 50 shots of the fully lubed 311466 Lovern bullet there really isn't a large build up of lube. It just gets blown off by the increased muzzle exit pressure.

Larry Gibson

136762

[1johnlb]

That's really good shooting. I see you are using powders and charges that work really well in other 1-14 twist rifles, Larry's Palma rifle being the number one test bed in 308 Winchester. I'm not too familiar with the bullet you are shooting, but I would be surprised if lack of lube is a limitation. The NOE XCB bullet has 3 VERY shallow lube grooves and doesn't carry much. I bet that just refining what you're already doing (casting and case prep have both been hurdles for me) will tighten those groups just fine. Good job.

Yeah, I've learned even the best leaders have to be good followers and then you have to decide rather to follow those who talk about doing something and those actually doing it. So is it really any doubt of the powders to use. Not to rub it in or anything bjornb, but my 8 lb jug of win760:D, lever,and 4895 should be pulling up in the next couple hours or so. I'm getting in deep, I've got a 06 barrel on order from shilen in 1-15 twist. The lady called me back that took my order and told me that I wouldn't be able to shoot out to 200 or more with that twist. I kindly explained to her what I was doing and she just made the statement, "oh, your one of those lead shooters". So, I kind of figured there must be more people calling about the slow twist barrels. So for the moment I'm shooting up the stock of other designs that better fit the 08 throat that I cast and stock piled during the winter, saving the 30 xcb for the 06.
136782
Dang, here's the gravity defying Lee 155 beside the xcb

[Bjornb]

Not to rub it in or anything bjornb, but my 8 lb jug of win760:D, lever,and 4895 should be pulling up in the next couple hours or so.


Good for you, and it's great to hear that you are taking the plunge into HV shooting. For me, that just means more results and targets to study! Excellent.

[Larry Gibson]

30x60 with Federal215 primers

Iretested H414 and conducted a psi work up on SuperPerformance powder (SpP) inDawn, my 30x60 with a linotype cast 30 XCB bullet last Thursday. The H414 in the 30x60 demonstrated the same inefficientignition and burning as was evident in the .308W Palma rifle when tested. The primer used in both cartridges was theWLR.

Theinitial psi work up of SpP was done with my usual 3 shot initial tests. 56 & 57 gr showed promise at 3000 fps +/-but still displayed a fairly high ES and SD both of velocity and of psi. It too was done with WLR primers.

Sinceboth those powders and LeveRevolution are ball powders of slow burning I suspectedthe use of a magnum primer might tighten those ES/SPs up so I loaded some testloads of H414, SpP and LeveRevolution powder using Federal 215 magnum primers. Iconducted the test of those loads this morning. I use the Oehler M43 PBL to measure the velocity and psi. What I found was interesting. The Federal 215 primers did indeed tighten upthe ES/SDs of both H414 and SpP powders. The use of the 215 primers provided no material affect withLeveRevolution powder.

Accuracywas very poor with the SpP powder.

Accuracywas more consistent with H414 but not acceptable (2 moa or less).

Accuracyremained consistent with LeveRevolution powder.

Solet’s see why by examining the data produced by the M43 of a load with eachpowder using the 215 magnum primers plus a test of my standard LvR load withWLR primers for comparison. Each of thetests shown was selected because they all showed a muzzle velocity of within 4fps of 2960 fps. The 10 shot groups aretraced on each data sheet. The bore ofDawn was cleaned for each powder test and 2 foulers were fired prior to recordtesting.

TheSpP load of 56 gr with the Federal 215 primer shows an excellent velocity SD of11 with an ES of 30 fps. The psi ran41,300 with and SD/ES of 400/1,500 which is also excellent. Note also the smooth and consistent pressuretraces. The same load over WLR primers gave a velocity SD/ES of 19/39 fps and apsi SD/ES of 2,400/4,900 for just the 3 shot test. The pressure traces alsoexhibited considerable erratic ignition characteristics. Thus we see the Federal 215 magnum primergreatly improved the ignition and burning of the SpP powder.

136856

[Larry Gibson]

TheH414 load of 53.5 gr over the Federal 215 primer also showed considerableimprovement over the same load with a WLR primer. Interestingly the muzzle velocity of the loadusing the WLR was 3013 fps with a velocity SD/ES of 24/75 fps. The psi was 46,100 with an SD/ES of 1,900/6,500psi. With the 215 primer we see the muzzlevelocity was lower at 2961 fps with the psi also lower at 43,400 and an SD/ESof 9/33 fps and a psi SD/ES of 600/1,800 psi…..a considerable improvement. The accuracy also improved slightly from 2.6”to 2.2”.

136857

The30 XCB load of 48.5 gr LvR powder with a 1/3 gr dacron filler over the Federal215 primer exhibited no essential difference from the standard load of 49.5 usingthe WLR primer. It just took 1 gr lesspowder with the 215 primer. The velocitywas 2956 fps with an SD/ES of 17/48 fps and a PSI of 44,600 with an SD/ES of1,100/3,200. The group was a consistent1.7”.

136858

[Larry Gibson]

Havingcompleted the Federal 215 testing and observing what appeared to be noessential change in performance with LvR powder (except for 1 gr less powder) butwith lower velocities and psi’s for H414 and SpP powders I decided to shoot atest string of the standard LvR load with the WLR primers to see if there wasany difference with that load. Therewasn’t any difference at all. That testresults fell right in the middle of the other past test results of load. The muzzle velocity was 2960 fps with anSD/ES of 8/27 fps and a psi of 44,400 with a SD/ES of 800/2,300 psi. The group was 1.65” excluding the 2foulers.

136859


Sohow is it that given a velocity spread of only 5 fps between the 4 loads, a maxpsi spread of only 2,300 psi between the 4 loads, SDs of 8, 9, 11 and 17 fpsand ESs of 27, 30, 33 and 47 fps the accuracy spreads from 1.65” to 4”? Given those very good, if not excellent internalsshouldn’t the barrel “nodes” be pretty much the same?

Well,at the velocity and pressures I’m pushing here it’s not the barrel nodes. When I push over 3000 fps the bullets begin toplasticize and the GCs come off which causes flyers, sometimes small andsometimes large, and that causes the larger groups. So is it the psi that causes that? Indirectly yes. What really causes the lossof accuracy we are seeing is the rate of acceleration. If you look at the data you see the SpPpowder gave the worst accuracy at 4”, yet it has the lowest average psi.

Don’tthink so? Well the devil is in thedetails. Look at the “Rise” data. That tells us the time in micro-seconds ittook for each shot to reach 75% of the psi. With SpP powder it took an average of 142 micro seconds. Now look at the LvR standard load with WLRprimers giving the best accuracy of 1.65”; it took and average of 242 microseconds to reach the 75% psi level. Thatis a considerable 58% slow rate of psi increase. That lower rate of acceleration is causingless damage to the bullet and not allowing plastization to start yet. We seethat in all the rise figures (the rise figures measure the burning rate of thepowder). The higher the Rise time thebetter the accuracy.

Interestingto note concerning burn rate charts; most don’t pay attention to the word “relative”in them. They can indeed be “relative” (wrongactually) as this test demonstrates. Asan example; The Hodgdon chart shows LeveRevolution powder at 106, H414 at 112and SuperPerformance at 129, I. E. LeveRevolution being faster burning thanH414 which is faster burning than SuperPerformance.

Yetin this test with the burn rates of those 3 powders measured we found just the opposite;SuperPerformance powder is faster burning than H414 powder and both of them arefaster burning than LeveRevolution powder! That said let me say the results could very well be different with othercomponents or in other cartridges. Thatis why such guestimates as Quick Load are only that…..a guestimate.

Thefun continues.

Larry Gibson

136860

[1johnlb]

Larry, does case capacity and percentage of case fill make a difference in powder burn rate. I think it was Bjorn that also had promise using a faster powder (3031) at lower case fill percentages.

Great write up!
Thanks

[Bjornb]

Larry,
Reading your report with great interest. Especially about the relative burn rates.
Take a look at my shooting from yesterday over in the Special Projects section. I got poor accuracy, ES and SD with SuPerformance, even though some of it can be attributed to the fact that I was pushing 140K RPM. LvR was somewhat better, but only at lower speeds. IMR3031 was a bust (too fast burning). H-414 continues to be the only consistent powder for my rifle in the higher MVs.

[dtknowles]

Larry

Thanks, as always great reporting and usually about something relevant.

"plastization" this of course is a nit but I don't like the word. I think the more proper term is Yielding?

Results in a permanent deformation. The mere fact that the bullet is engraved by the rifling does cause yielding but (I understand you desire to be more specific), when the accelerations are greater than some limit more gross deformations take place. The alloy yields to the forces since the stress level is in the plastic range.

Tim

[leftiye]

Exceeds the elastic (elasticity?) limits of the metal?

[Larry Gibson]

I use the term "plasticize" defined as; "undergo a change; become different in essence; losing one's or its original nature".

At the pressures, heat and acceleration rate the bullet, particularly at the base, begins to soften becoming putty like. As the cast bullets in this instance is accelerated beyond 3000 fps this may not be happening to the entire bullet but just in places where the pressure s greatest. That would most likely be at the base of the bullet, exactly where the GC is crimped into the alloy. If the alloy gets soft and putty like at that point then the higher friction coefficient of the GC would cause it to be "dragged" off the base of the bullet. That could explain why the GCs most often appear to be separated from the bullet on muzzle exit. This is proven by the severe damage done to the screens which are only 15' from the muzzle.

"Yield", as you use it, refers to deformation of the bullet by the rifling. That of course does happen at all levels of velocity when a bullet is fired from a rifled barrel. "Plastization" refers to a change in the "state" of the alloy itself, i.e. the alloy becomes softer and perhaps "putty" like.

It takes pressure to produce velocity. The pressure required for 3000+ fps with any of the slower burning powders used thus far exceeds 40K psi and in many instances exceeds 50K psi. That is well above what is generally accepted as the "elastic limits" of the common ternary alloys used. Obviously we are into an area of pressure and velocity few have ventured into previously with the degree of success we've had. There is more than like several things occurring to the bullet we were not previously aware of. I'm simply describing what appears to be happening with the terminology that best describes it that I know. Doesn't matter what you call it or I call it as it is still happening. The trick will be to understand what is happening and see if we can get through or around it. Maybe we can and maybe we have reached the limits of how fast we can push a ternary cast bullet with accuracy.....I don't know.....yet.

Larry Gibson

[Larry Gibson]

Bjorn

I checked out the "Special Projects" post and found it interesting.

If I may suggest a couple things;

Switch to magnum primers (250s, WLRMs or 215s) for use with H414 and SpP powders.

Use a 1/3 gr Dacron filler with your LvR loads.

The RPM Threshold top end of 140,000 RPM is at 2722 fps with a 14" twist. Most of your loads are close to or above that. My own groups in that same velocity range using my 14" twist Palma .308W resembled yours. I was never able to get consistently good accuracy above 2700 fps. Suggest you drop the powder charges of H414, SpP and LvR powders down to below 2600 fps and work back up. I've found the best and most consistent accuracy with my Palma rifle to be right at 2600 fps. I can sneak up to 2700 fps with LvR and maintain useable accuracy (under 2 moa) but it is not as consistently good as with the 2600 fps load.

Also I have yet to find a need to anneal any .308W or 30x60 case necks used for HV cast bullet shooting. Having chased my tail on the "annealing" issue to no avail attempting to improve accuracy I don't waste my time on it any more. However, I do anneal case necks when they become brittle to prevent splitting is all.

Many also erroneously assume when the turned neck is sized down after firing the brass goes back to the original shape and thickness. It may go back close depending on the expansion and resizing but it is never the same and it is always different. That's why after turned necks are fired several times you can run the turner back over them and find you have high spots being turned off. That's because the brass gets thicker in some spots and thinner in other spots. There are a lot of things we can do and can control for "consistency" but attempting to control bullet pull so it is exactly the same is not fruitful. There will always be some difference. Every time we size necks the seating pressure and bullet pull will be different. You can never keep it exactly the same unless you use a "slip fit" neck. But even that induces other variables into the game. The differences in neck tension is not what's causing the inaccuracy, the higher RPM is.

Larry Gibson

[detox]

A big heavy bench rest rifle with long, wide, flat forearm will take most of the shooter error away.

[popper]

Larry - 100yd targets?

[Larry Gibson]

Larry - 100yd targets?

All my testing is at 100 yards with CF rifles. I throw the targets away when I print out a data sheet after the groups are traced on the data sheets. With all the shooting and testing I do keeping the targets and cataloguing them some how would be more than I want or need to do. I already have shot 90+ test groups out of Dawn. Keeping just the data sheets in a binder is enough record keeping for me. You can see the groups in the post on the data sheets. I did take a photo of a couple groups at the range though. Rotate the photo to the right to see how it actually was.

Larry Gibson

136893

I also took anther photo of the 3003 fps load using 49.5 gr LvR with the Federal 215 magnum primer. Velocity SD/ES was 3/41 fps with the psi being 46,900 with an SD/ES of 700/2,300 psi. The rise was slow at 225 micro-seconds. Again excellent internals but the externals, while showing real promise, sucked. Notice the nice 6 shot group where it should be. The shot out a 3 o'clock I actually saw the GC come off down range through the scope. Notice the larger and not quite round holes the 3 high flyers made. The GCs of those 3 came off on muzzle exit and damaged the screens.

136896

[Larry Gibson]

A big heavy bench rest rifle with long, wide, flat forearm will take most of the shooter error away.

I built Dawn to be somewhat useable in the field. The forend is standard sporter contour and she weighs only 12.5 lbs. Thus recoil can induce some error into the groups for sure. I have "called" several shots due to shooter error in my testing.

Larry Gibson

136894

[cainttype]

I think I lost ANOTHER "XCB" thread in the Special Projects sub-forum... Anybody seen it?

[cainttype]

Dang it!... There it goes again.
Here today, gone tomorrow...

[kens]

When you say the boolit is plasticizing, and gas check pops off, how do we know that the nose is NOT falling apart as well?
Consider this: if 1000fps is Mach1 (speed of sound) then 3000fps is traveling at Mach3.
History tells us that supersonic aircraft in the Mach3 category have titanium leading edges to take the heat buildup. Yes, at mach3 the air friction heats things up to the point that heat treated aluminum loses its heat treat.
So then, how do we know whether or not our boolit nose is falling apart at that kind of speed?
If you think about it, all the high speed jacketed bullets have a minimal lead point showing, if any lead at all. The high speed hollow points are usually a hollow copper nose, no lead.

I propose a test of a bullet like a .35rem, .30-30 or soft nose .30carbine (big lead nose) and drive it on up to 3000fps and see if it also falls apart at that speed.

[1johnlb]

Looks like the 30xcb thread is gone.

[Bjornb]

I believe the thread was taken down for Mod review due to extensive trolling by one or two posters. It seems to happen from time to time.

[cainttype]

I hope you're right, Bjornb. There's too much good data contained there to waste.
Perhaps the "High Velocity With Cast" thread could be resurrected by those HV enthusiasts that aren't interested in keeping the "Testing the 30 XCB" thread on track. It would seem too easy a solution, much better than the regular interruptions that have followed the XCB threads.
The efforts you, Larry, and Tim have made to post your test results here on CBs is much appreciated by many.

[Larry Gibson]

When you say the boolit is plasticizing, and gas check pops off, how do we know that the nose is NOT falling apart as well?
...........

We know its the GCs coming off and not the nose melting off because the bullet holes in the target are still round and show no evidence the nose is melting or deforming. We know it's the GCs coming off because it is they who are severely damaging the Skyscreens of which the start screen is 15' from the muzzle. Note in the pictures the severe damage and in some cases perfect 30 caliber holes neatly punched into the face of the Skyscreens. Additionally several GCs thus have been recovered from the inside of the Skyscreens.

Note in the picture of the recovered GC from inside of a Skyscreen how the alloy is soldered to the inside of the GC. That only can happen if the alloy becomes molten at high temperature inside the barrel and the bullet base is still molten or "plasticized" allowing the GC to come off immediately on exit from the muzzle. The velocity of the bullet that lost that GC was 3100+ fps out of the 30x60 XCB (Dawn). The evidence of plasticization as left is how we know. Bjorn B was with me at the range when that GC was recovered from inside a Skyscreen.

Larry Gibson

141927141928141929141924141925141926

[MBTcustom]

That evidence pretty much sums it up.
I find it amazing that a mere GC can produce that much damage. That alone demonstrates the fact that "this little dude was cooking right along at extremely high velocity!!!!"
I've never seen a GC do that before.

[kens]

I have heard that cast boolit can be driven at either high velocity, or, high pressure, but NOT both.
With that in mind, then how can we determine to what pressure/velocity we can drive a boolit before the gas check melts off?

[MBTcustom]

I have heard that cast boolit can be driven at either high velocity, or, high pressure, but NOT both.
With that in mind, then how can we determine to what pressure/velocity we can drive a boolit before the gas check melts off?

Well, seeing as how there is such a deficit of information about shooting cast bullets at HV, the XCB project was started to answer questions just like that.
We shoot. We keep records. We post the results. We keep track of what works and what doesn't. We back up everything with groups posted right up front, every step of the way.
It's new ground.

So far, the trick is finding powders that give a good balance. With the original 30XCB, powders such as Leverevolution, and H414 are pretty good choices (I'm enjoying LvR very much indeed!). I expect Larry is finding slower powders that give satisfactory results.

[Larry Gibson]

I have heard that cast boolit can be driven at either high velocity, or, high pressure, but NOT both.
With that in mind, then how can we determine to what pressure/velocity we can drive a boolit before the gas check melts off?

As usual such statements are an over simplification. The problem in the simplification is what is actually meant by "high velocity" and "high pressure".

Since I measure both velocity and pressure here is what I've found. As with many things involved in shooting it depends on variables. With the 30x60 XCB cartridge using a 30 XCB bullet cast of either #2 alloy or linotype plastization of the bullet alloy at the base of the bullet seems to occur in the 2950 - 3050 fps range. It seems a pretty consistent occurrence above 3050 fps with bullets fired from the cartridge case. Breach seating appears to allow a bit higher velocities to be attained before this "plastization" of the base of the bullet occurs.

The range of psi where plastization occurs in the 45,000 to 54,000 range. The psi where this occurs is not consistent but seems dependent on the time pressure curve of the powder. The powders with the slower time pressure curves seem to cause plasticizing at somewhat lower velocities. This may be due to the longer exposure of heat and pressure to the base of the bullet during the slower time pressure curve(?).

By my definition I am driving cast bullets out of slower twist (14 & 16") rifles at both high velocity (2400 - 2900+ fps) and high pressure (40,000 - 54,000+ psi) and maintaining usable accuracy (2 moa or less) at longer ranges (300+ yards). Thus the above premise of that statement is not correct such as it is with many myths involving the shooting of cast bullets, especially at "high velocity".

As goodsteel points out: "We shoot. We keep records. We post the results. We keep track of what works and what doesn't. We back up everything with groups posted right up front, every step of the way. It's new ground."

It is indeed "new ground". I am not sure I am going to pursue this much further as it is hard on the test equipment which the replacement of can be expensive. It will be interesting to see what results BjornB gets with his 17" twist rifle chambered to the full 30-06 cartridge to XCB chamber specs.

Larry Gibson

[popper]

Primarily pressure induced 'heating'. Supposedly 20% of powder energy goes into expanding the barrel, making it 'hot', does the same to the boolit base. Powder burn temp adds some temp but not a lot. I found one GC from 308W, lead left in the GC was silvery - rest of the boolit was gone. The lead crumbled easily. That one cut through 12 ga steel wire & the remains are someplace in a rock pile. Don't believe the pressure thing? FL size a 308 case and feel the temp.

[kens]

Larry quote:
"I am not sure I am going to pursue this much further as it is hard on the test equipment which the replacement of can be expensive."

What is your equipment? Copper crushers? Strain gages?
strain gages should be relatively inexpensive.

[Larry Gibson]

Depends on what you consider "relatively". It is the Skyscreens that get damaged by the errant GCs. I use an Oehler M35P when just chronographing. I use an Oehler M43 PBL when measuring screened velocities, pressures, time/pressure traces and TOF (Time of Flight) muzzle velocity along with other data. The Skyscreens can be somewhat expensive and it totally disrupts a range session when one is shot and is destroyed or misreads. There are 3 Skyscreens required for the M35P and 6 of them for the M43. I have already replaced several of them. The strain gauges do cost money and as they are permanently attached to a test firearm/barrel which also costs money. I currently have 30+ firearm/barrels for various cartridges with strain gauges attached for testing. Additional the M43 and the computer to run it on are not inexpensive nor is the generator and attendant equipment to operate it. I consider my time as valuable also and testing in a scientific manner to get consistent, reliable and reproducible data is not a matter of stepping down range and slapping a Chrony out there.

All of this has been covered by me in the numerous posts/threads I have been giving information on. You might do a search and read some of them for more precise descriptions of the equipment I use and the testing done.

Larry Gibson

141939141940141941141942

[kens]

are you reading strain gages pressures directly on the laptop?
I work with strain gages but we go through a analog/digital converter before it gets displayed on laptop.
That is quite a good setup you got.

[Larry Gibson]

The Oehler M43 receives the input from the strain gauge and feeds into a program on the computer. The screens, muzzle and down range, also feed into the M43. Data on the load, the test firearm, the physical setup and the current conditions are entered into the computer program. The data from each shot is measured and converted to usable data by the M43 and the computer.

Larry Gibson

[runfiverun]

I just pound them on the table top...
that usually squares them up and bashes them into place good nuff.
:kidding:

[Larry Gibson]

Received a question regarding the "plastization" of the bullet. Question was; "Wouldn't leading of the barrel occur?"

Fact is leading of the barrel did occur. As BjornB can attest after testing the loads (3050 - 3100+ fps) where the GCs were being lost and we had to fix the Skyscreen before testing could continue the accuracy with a standard load in the 2950 fps range that normally give around 1.5 moa accuracy shot poorly with 2.5+ moa accuracy. A normal cleaning of the barrel did not removed the leading as accuracy at the next shooting session was again 2+ moa with proven loads. I used JBs on a patch over an undersized brush to remove the leading and accuracy resumed back to 1.5 moa average for the 2950 fps loads.

Larry Gibson

[kens]

With all this testing can we assume the following as proven results?
1. Slow twist allows us to duplicate Mauser military load velocities using gas checked boolits.
2. Chamber, neck, throat, other tight tolerances allow us to tighten groups at said mauser velocity
3. barrel leading comes from the base of the boolit, not the boolit stripping the rifling, nor the sides of boolit

I am asking these 3 things because of the most common discussion items regarding high velocity cast. Not to be all inclusive here, but to respond to the most common high velocity subjects.
All these 3 things are assuming lube is up to the task, and boolit fits the bore, and quality barrel is used.

Are these a fair assumption of tested results?

[MBTcustom]

Very fair, in my humble opinion. In fact, duplicating 8mm Mauser performance with cast is a very easy thing if a slow twist barrel is used.
2600fps? Totally plug and play, slam dunk, home run.
Heck you don't even need to use Linotype or anything special to get that.
Here's my last range session results using House alloy which is nothing more than COWW carefully balanced with tin to get 95.6/2.2/2.2. BHN of these bullets was 24. Hardly rock hard alloy:

Rifle is a 1909 Argentine rebarreled to shoot 30XCB.
Powder used for these groups was Leverevolution.
Speed was between 2650 and 2700fps
141971
141972
141973
141974
141975
141976
141977

[Larry Gibson]

kens

Yes, those are fair assumptions considering "8mm Mauser velocities" runs from 2400 to 2950 +/- fps depending on which cartridge and rifle (with attendant barrel length) is used. Certainly the accuracy level of military 8mm (8x57) ammunition can be attained and most often bested with a properly designed and cast bullet in slower twist barrels of equal length.

Shown is what 2975 fps looks out of the 16" twist rifle. This was shot with #2 alloy when the ambient temperature was close to 70 degrees. I have not been able to duplicate that with linotype w/o plastization occurring when the temperature is above 80 degrees. The diamond is .75" on a side.

Larry Gibson

141982

[kens]

I'm going to respond in 2 posts, and ask you guys to respond in return, if you don't mind.

1. Pressing cast boolit to the 3,000fps class is a tremendous accomplishment. I got a mauser up to 3,000+ but it was a 29" Swede with a little 85gr jacketed pill. To get anywhere near that with a 160gr boolit is just outright awesome. You've gone past bore leading, stripping the lands/grooves, pressures, and all that. You went to the point of melting the gas checks off the shank. That is remarkable.
So now I guess we know the limit of shooting cast……………the limit is melting the gas check off.
All the Mausers models 91, 93, 95, 98 were made for jacketed ammo. You guys have arrived at Mauser velocity with cast. Job well done.

[kens]

2nd part of my post:

Can you guys post a sticky outlining how the rest of us can get to 'Mauser Performance with Cast' ???
Do we need to turn case necks? Do we need special tightened chambers? Do we need XCB molds?
It is no secret that accuracy stems from neck fit, rifling leade fit, and other bench rest technique, BUT, do we need to go to that extremes to get duplicate Mauser performance?
Can we use regular brass and regular molds?

You have done a scientific clinic on this, can you pass along the basics for the rest of us?
Thanks for your time and experience.

[1johnlb]

So now I guess we know the limit of shooting cast……………the limit is melting the gas check off.


That limit may very well be set, in and around the 3000fps range with ww and lino, but could possibly be pushed higher with a copper enriched alloy or other alloys. But that's yet to be seen and outside of the original test parameters.

[popper]

The range of psi where plastization occurs in the 45,000 to 54,000 range.

Fact is leading of the barrel did occur. Interesting clues. Also, accuracy should suffer as this point is approached, plastic lead is forced in front of the GC, flowing where there is no lube (or it's already pushed out). Maybe a longer GC is needed?

pushed higher with a copper enriched alloy Not sure this shouldn't be in the parameters, but? Bjornb tested some the Cu enriched with good results. I've gotten my 308W 1:10 to 2640, should be close to Larry's tested pressure (H4895), Cu enriched alloy. Actually one hit 2789 & paper. More testing to do for accuracy but first try was almost acceptable. Not into HV testing but the 30XCB gave me a bug.

[cainttype]

There is a lot of ammo prep archived here on CBs. A good source of fairly recent discussions relating to it can be found in the "High Velocity With Cast" thread.

The "Testing the 30 XCB" thread contains detailed results of tests with XCB rifles, the XCB mould (as rendered by NOE), the XCB case, and various combos utilizing 1, or more, of the 3.
While most results posted there have been with XCB rifles using slower-than-most twist rates, it was hoped that results using fast twist barrels would also be posted.
I know I'd like to see anything posted that could be considered as actual results, by any twist rate at any comparable velocity.

This thread was started to explore the actual results of slow-twist barrels using any cartridge/mould combo.
Although the XCB concept is proving to be very practical, the intention here is to encourage the constant "pushing" of what we think the limits might be. Has the limit been reached???... I doubt it, but fully expect the guys here to try to find out.

[Larry Gibson]

I know I'd like to see anything posted that could be considered as actual results, by any twist rate at any comparable velocity.


I posted a couple threads on the NOE forums of HV testing done in 10 and 12" twist .308Ws.

Larry Gibson

[cainttype]

I know I'd like to see anything posted that could be considered as actual results, by any twist rate at any comparable velocity.


I posted a couple threads on the NOE forums of HV testing done in 10 and 12" twist .308Ws.

Larry Gibson

I read those posts with much interest when you put them up, Larry. It was well written and in great detail. Info like that is great reference material.
I'm hoping that as more people get interested in the different aspects of HV pursuit they will feel like posting the results of their tests, adding to the wealth of info already archived here. If they haven't already been included, I'd like to see those 10" & 12" twist test results copied and pasted here in the XCB thread for ease of reference.

[Slowpoke]

That evidence pretty much sums it up.
I find it amazing that a mere GC can produce that much damage. That alone demonstrates the fact that "this little dude was cooking right along at extremely high velocity!!!!"
I've never seen a GC do that before.

I have, my sky screens are all spliced together with wood paneling strips and duct tape from 35 cal gas checks, never had a problem yet with 30 cal GC's.

I think it will be interesting when you intrepid fellows get the 35 XCB project moving forward.

I appreciate all your efforts, FYI your 35 XCB fits my BLR chamber like it was made for it.

Thanks and good luck

[MBTcustom]

I think it will be interesting when you intrepid fellows get the 35 XCB project moving forward.

I appreciate all your efforts, FYI your 35 XCB fits my BLR chamber like it was made for it.

Thanks and good luck

Good to hear! I was hopeful the 35XCB would be as versatile as the 30XCB (concerning Fit), and reports I am getting from hither, thither and yon have validated my hopes.
I just chambered two more rifles in 35XCB last night, so hopefully we will be seeing good results soon as well.
Personally, I'm even more excited about the 35 as I was the 30. Not only because I think it will be an even more plug and play LR hunting option, but because if it's as successful as the 30, it means that the calibers between those two goelposts (.323 and .338) are in the bag, and it's looking pretty good for a .375 option as well. We shall see.

[popper]

Larry, Bjornb and others have put a lot of effort and expense into testing HV cast, many thanks. And Happy Birthday Army. Contemplating the 'plasticisation' threshold at those pressures, IMHO it's the tin that causes it. Lower melt temp. Both alloys tested have high tin content. From observation, tin is easier to 'melt' off a chunk than lead which has to get the entire ingot to temp before any 'melts' off. Lino & #2 are good reference alloys for data points.

[kens]

I don't think alloy matters. Tin or no tin. Any alloy that we use on this forum is going to melt at the pressure & temp of 3,000fps. We all cast with alloy approx 600f be it lino, #2, or a house alloy, it is still approx 600 degrees F and any of it is going to give up the gas check around 3000fps. Plus or minus a few feet/per/second isn't going to really matter. Whatever alloy it takes to sustain the 3000fps threshold isn't going to melt & cast with our current equipment and molds. Copper enriched alloy temperature goes up exponentially with the copper content. With our current equipment we can only enrich with copper up to about .25% before the temp needed rises out of the range of our equipment. The next step in the quest for 3000fps is going to be a alloy that melts at a higher temp, and our lead pot & mold won't get us there.

What we CAN do however, is duplicate Mauser speed. With Mauser speed being about 2400-2800fps, we can do that with our house alloy that we all use on this forum.
What we cannot do is 3000fps and upward such as the jacketed magnums.
Mauser speed with cast is very good indeed.
I appreciate the efforts to those that did this research and testing, A job well done.

[cainttype]

With this thread's intent, posting results from "slower twist" barrels pushing cast at HV (the higher end of factory ballistics), I'm hoping to see results from any rifle/combo that achieves the goal.
The XCB tests are proving that 3000+/- fps with a .308 165 gr cast is a realistic goal with their components and test beds. However, a 375 H&H pushing a 250 grain cast at 2700 fps would meet the goal here just the same...But is it easier with a 1-16" compared to a factory 1-12"?
Compiling HV test results in rifles with slower-than-standard twist rates is the purpose, so I'd rather not give potential contributors to the thread the idea that 3K speeds are necessary to post beneficial data here.

I'm anxious to see the forthcoming results of the 35 XCB tests. Like Tim said, the .323, .338, & .375s are a natural progession... Lots of things to look foward too.

[1johnlb]

Good to hear! I was hopeful the 35XCB would be as versatile as the 30XCB (concerning Fit), and reports I am getting from hither, thither and yon have validated my hopes.
I just chambered two more rifles in 35XCB last night, so hopefully we will be seeing good results soon as well.
Personally, I'm even more excited about the 35 as I was the 30. Not only because I think it will be an even more plug and play LR hunting option, but because if it's as successful as the 30, it means that the calibers between those two goelposts (.323 and .338) are in the bag, and it's looking pretty good for a .375 option as well. We shall see.

I've always dreamed about having a 35 Whalen, but what pushing a 225gr boolit at 2500-2800fps does to a shoulder was never part of it. So, I'm going to sit on the porch and observe the big dogs on that one.


cainttype

With this thread's intent, posting results from "slower twist" barrels pushing cast at HV (the higher end of factory ballistics), I'm hoping to see results from any rifle/combo that achieves the goal.




Just got my 30/06 Shilen 1 in 15 sit up, with some 311299s loaded over Magpro and RL22 for fire forming the cases. I'm very interested in seeing how the magpro performs. Still got to sort and prep some xcb's to load next, fit is much better in the 06 than it was in the 308w.

[Bjornb]

I don't think alloy matters. Tin or no tin. Any alloy that we use on this forum is going to melt at the pressure & temp of 3,000fps. We all cast with alloy approx 600f be it lino, #2, or a house alloy, it is still approx 600 degrees F and any of it is going to give up the gas check around 3000fps. Plus or minus a few feet/per/second isn't going to really matter. Whatever alloy it takes to sustain the 3000fps threshold isn't going to melt & cast with our current equipment and molds. Copper enriched alloy temperature goes up exponentially with the copper content. With our current equipment we can only enrich with copper up to about .25% before the temp needed rises out of the range of our equipment. The next step in the quest for 3000fps is going to be a alloy that melts at a higher temp, and our lead pot & mold won't get us there.

What we CAN do however, is duplicate Mauser speed. With Mauser speed being about 2400-2800fps, we can do that with our house alloy that we all use on this forum.
What we cannot do is 3000fps and upward such as the jacketed magnums.
Mauser speed with cast is very good indeed.
I appreciate the efforts to those that did this research and testing, A job well done.

I hate to be the fly in the ointment here, but your post is so riddled with inaccuracies that it begs a reply. Please take the time to read this thread from the NOE forums:http://noebulletmolds.com/smf/index.php/topic,541.0.html

All groups were shot with linotype (4% tin). At speeds above 3000 fps there was no melting of alloy, and no gas checks came off. I ran out of case capacity with the powder required to keep pressure sufficiently low.

I expect to reach speeds around 3500 fps with 2 MOA accuracy with my new barrel (Shilen, 1:17 twist), bullets breech seated. Monotype (9% tin) will be alloy of choice).

And btw those of us involved in the XCB project cast at right around 740 degrees.

[popper]

Kens - I cast for the 308W with 1% Cu, no problems. Actual first try was 50/50 #2/pure with Cu replacement of tin so probably close to 2% Cu, 720F (PID controlled). Didn't do well in the 308, I had to add more Sb. My thought on the tin was aimed toward larry's problem with GCs, I do believe it to be correct whether Bjornb has the problem or not. I was chronying last week and got a 2789 fps reading on one round - book max for jacketed for 170 gr. in a 24" AR - nowhere near the quality gun they are testing with. My 'house' alloy of 3% Sb/~0.7% Cu, NO tin - cast about a year ago.

[kens]

I hate to be the fly in the ointment here, but your post is so riddled with inaccuracies that it begs a reply. Please take the time to read this thread from the NOE forums:http://noebulletmolds.com/smf/index.php/topic,541.0.html

All groups were shot with linotype (4% tin). At speeds above 3000 fps there was no melting of alloy, and no gas checks came off. I ran out of case capacity with the powder required to keep pressure sufficiently low.

I expect to reach speeds around 3500 fps with 2 MOA accuracy with my new barrel (Shilen, 1:17 twist), bullets breech seated. Monotype (9% tin) will be alloy of choice).

And btw those of us involved in the XCB project cast at right around 740 degrees.

I had read Larry Gibson post #243 regarding the gas checks melting off.
No offense taken.

[cainttype]

I expect to reach speeds around 3500 fps with 2 MOA accuracy with my new barrel (Shilen, 1:17 twist), bullets breech seated. Monotype (9% tin) will be alloy of choice).


Now that's an ambitious goal!
I don't think I've ever heard anyone pursue 3.5K with a 30 cal hunting weight cast. Should be very interesting.

popper, can you give an average velocity with groups attained (photos are always nice, if possible), and/or data on load components?
I didn't catch much info on the rifle you're using for testing. Could you give a few details?

[Bjornb]

I had read Larry Gibson post #243 regarding the gas checks melting off.
No offense taken.

And no offense was meant. I guess I'm just getting a little touchy about what's being concluded regarding HV shooting; there are just so many variables that have to be considered, and until something has been tried in multiple configurations I'm always hesitant to make firm conclusions.

I do appreciate your interest in the project; keep the questions and comments coming.

[Larry Gibson]

I had read Larry Gibson post #243 regarding the gas checks melting off.
No offense taken.

That seems to be the quandary; BjornB didn't seem to have the GC problem and I did. Not sure he didn't though as his chronograph doesn't use screens. Can't tell by the hole in the target if the GC was still on. I was losing GCs of 1 - 3 shots in some groups (10 shots) that still were in the 2.5 - 3.5 moa range. I know the GCs came off those because they hit the screens.

The M43 Data sheet of a test using 53.5 gr H414 with the 30 XCB bullet out of the 30x60 (Dawn) at 3013 fps shows the loss of the GC doesn't necessarily produce a really wild flyer. Notice shot #10 is the only one that lost the GC. #10's velocity was not the highest nor was the peak pressure the highest of the test string. Notice the TOF of #10 was however the slowest (longest TOF time) and the resultant BC being the lowest of the test string. This phenomenon is new to us and we don't have all the hard and fast answers yet. The testing is still continuing at these higher end velocities so trying to put it down in a "sticky" as something hard and fast to follow is probably not a sound idea yet. However, with the 30 XCB cartridge (30x57) in at least a 26" barrel with a 14" twist will yield "Mauser" velocities of 2400 - 2700+ fps w/o such travails.

Larry Gibson

142107

[popper]

Cainttype - not involved in this testing but interested. Posted results in coating accuracy thread. 24" AR10 off the shelf. My best guess that one shot was low neck tension and setback in ~90% load capacity - definitely NOT on purpose. The rest, 4 shots were right at 2595 avg, ES=15. Probably close to 55K psi.

[1johnlb]

Bjornb

I expect to reach speeds around 3500 fps with 2 MOA accuracy with my new barrel (Shilen, 1:17 twist), bullets breech seated. Monotype (9% tin) will be alloy of choice).




Bjornb, how long is your Shilen 1in17? I chose the 15 because of Shilen's 30" finished limit and a desire to still shoot some heavies.

[MBTcustom]

Bjornb, how long is your Shilen 1in17? I chose the 15 because of Shilen's 30" finished limit and a desire to still shoot some heavies.

I can answer this and Bjornb cannot as the barrel was just recently chambered, threaded and crowned here at MBT and the rifle still resides here.
It is necessary to cut 1" off the muzzle end of the barrel (more or less) in order to achieve accuracy. The blank was shipped about 1" long (27.75") so the finished length after crowning is 26.75".
Also headspaced to this rifle is a 30" Brux in 30XCB, and a 29" Shilen in 35XCB, both of which are 1-14 twist. We have a twitch barrel Mauser. :D

This is being done on my own Felix rifle, and loaned to Bjornb to continue testing while the Bertha rifle is being overhauled.

[kens]

Quote Larry Gibson:
" However, with the 30 XCB cartridge (30x57) in at least a 26" barrel with a 14" twist will yield "Mauser" velocities of 2400 - 2700+ fps w/o such travails."

Quote Goodsteel:
"this rifle is a 30" Brux in 30XCB, and a 29" Shilen in 35XCB, both of which are 1-14 twist"

OMG !!!!
I'm having a vision!!! :kidding:

One of us has a old RIFLE length Mauser (29"bbl) that we fit a replacement bbl (XCB), stepped contour, complete with original dress hand guards, bbl bands and all.
What a sleeper of a rifle!!!
Launching old WW's!!! :lol:

[Bjornb]

Yeah that would work I guess:
142131
However the ruse would fall apart once I had to mount my Weaver T36 scope on it in order to see the target!

[runfiverun]

I'm wondering if the linotype alloy isn't too brittle at the higher speeds and is breaking at the crimp point of the gas check.
the boolits are still fling fairly straight [2.5' groups] but the gas check ain't really needed after it leaves the barrel.

I have heard of many high Sb boolits breaking off at the crimp groove during loading or if dropped.
the crush of the gas check could be causing this to happen.

[Larry Gibson]

No indication of any part of the bullet that may have broken off hitting the Skyscreens. All damage is being done by the GCs.

If the base of the bullet doesn't melt then can someone explain the soldered alloy on the inside of the recovered GCs?

I have mentioned numerous times over the years on several of these threads that with many bullet designs don't do well at HV when cast of linotype due to the brittleness of the antimony rich alloy. I have described how the back edges of the drive bands have chipped and broken off from the land engraving. This was found on otherwise undamaged recovered bullets shot into snow. My recent HV tests using the .308W and the 30x60 XCB seem to verify that linotype is not as accurate as is #2 alloy at the top end velocities above 2700 fps in the 14 and 16" twist rifles. I'll be switching back to #2 alloy and also COWWs +2% tin in the next series of tests. I compare the results using those softer alloys closely with the results of the linotype bullets using the same loads in the 2700 - 3000+ fps range.

As mentioned several times ; this is new territory shooting cast bullets with consistent usable accuracy above 2700 fps and into the 3000 fps range. Some different things are happening that we are not sure of what or why yet. Only further and more complete testing will tell us the answers. However it's a pretty good sure thing that the 30 XCB cartridge in a 14" twist barrel with at least a 26" barrel will get you very good results with cast bullets at least into the 2600+ fps range and higher with a longer barrel.

Larry Gibson

[Nrut]

Larry,
How does Leverevolution behave pressure wise in different ambient temperatures in the .308 case?
The reason I ask is Leverevolution is sometimes available at the LGS while I haven't seen any other powders there (other than Trail Boss) for almost 9 months..
Canadians have finally taken up "hoarding"..
Should add that I will be using jacketed bullets..

[Larry Gibson]

Nrut

Wish I could give you a definitive answer but I've not tested it enough across a wide temperature range. I can say that the same load here in Arizona picks up about 25 - 40 fps between 60+ and 85 - 90+ degree's. At 60 - 70+ degrees the velocity of my 49.5 gr load runs 2940 - 2960 fps and is quite accurate (averages 1.6" for 10 shot groups). At 85 - 90+ degrees that same load begins to lose GCs with the velocity in the 2965 - 2990 fps range.

Larry Gibson

[Nrut]

Thanks Larry..
It very seldom gets over 80*F here and I don't shoot then so I won't worry about temperature insensitivity..
I will be using 308 Marlin Express data to start with which Hodgdon gives data for..

[Larry Gibson]

I suspect LvR will work very well in the 308 Marlin, especially with the 160 gr Fex Tip Hornady makes for that cartridge.

Larry Gibson

[1johnlb]

Larry or Tim has anyone considered reducing the size of the 30xcb by 15 or 25 grs in order to make case efficiency better to lower pressures and accommodate the slower twist while increasing velocity? With the slower twist it seems to me that bearing surface for the purpose of strength could be reduced to yield higher velocities. But maybe my train of thought is wrong.