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?

[swheeler]

cainttype: no results here because I don't have a slow twist barrel YET. I do enjoy reading the threads and like to see the data and targets provided, some amazing velocities and usable accuracy are being posted, then only to have them disappear! I for one want to see this information!

EDIT- We all are losing out on valuable information here, let's not let personal spats ruin it for everyone! I was following the xcb thread and saw nothing that was wrong, just information being given, why did the thread disappear, makes no sense.

[MBTcustom]

There's no reason that BOTH methods should not be discussed in the same thread. I have conducted independant tests on both methods and found some merit to both. Those that would say the HV with fast twist barrels method is worthless are very much mistaken. If you have the wherewithal to persue that method (it's expensive and time/component consuming) then you are able to go much further than your twist would normally allow with a normal cast bullet of some alloy (it remains to be seen if these results are linear past 100 yards though).

Those who would say the HV with slow twist barrels method is worthless, are obviously ignoring the plethora of tiny groups at blazing fast speeds that have been posted in this forum and others, and the ease with which those results were achieved.

I am am not in either "camp" and never have been. I have bent over backwards to get EVERYONE shooting to their best potential. I recognized the greater difficulty that the HV with fast twist method presents, so I built THREE rifles for geargnasher, Btroj, and run5run with the understanding that the results would be posted, and barriers would be broken down.

In the mean time, I have been employed by BjornB, and others to build slow twist rifles. Nearly every group that has been shot has been posted and the evidence is clear. Slow twist gets you there ASAP and on the cheap.
Shilen sells barreles in slow twist for $200 (any profile you desire) and I charge $175 to fit that barrel to your rifle. Bjorn and Larry can back me up on this. They have both used MBT rifles, and they will both tell you that the results were insantanious.
My results are biased, so take it with a grain of salt, but I will just say that my experience with Bjorns old barrel using his loads put me at a higher velocity, with better accuracy than I ever could get with my standard Remington 10 twist barrel (understand that I did not shoot the required 2000 bullets with various alloys that the HVWST crowd recommends. I shot about 500 and ran out of money and components, and with no posted results even close to those of Larry Gibson's, I shamlessly decided to see what makes the cow go moo with the slow twist method).

I am totally convinced that the slow twist method is the quickest, easiest and cheapest, but I'm ready to get back to shooting HVWST method because I am now in a better financial situation, and I'm hoping to get 3000fps with fixed ammo in my rifle. The problem is, no matter who's method I'm currently studying, I get slapped by the other group for being a two faced turncoat!
Seriously guys?!?!? And I was accused of being biassed?!?!?

let me be very clear: I'm here to learn how to shoot. I want to learn every method ever devised to launch a cast bullet. I want to shoot cast from every position ever devised to shoot it from. I want to shoot cast in every firearm ever devised to shoot it from, and I want to help others to do the same.
I thought that the forum would support that, and encourage members who desire that diversity of education. This fighting and choosing sides makes it nearly impossible for a man like me to learn from this forum without assuming multiple identities and fighting with myself online.
Thats rediculous.

[MBTcustom]

No Brad. There is nothing to get back to. It's an ongoing discovery of the previously impossible on both sides.

Right now, we are trying to see how fast a bullet can really go. In this thread twist doesn't matter. The fellers are not limiting themselves to certain twists, certain weight classes, certain bullets, certain lubes etc etc etc. It's all about speed, and do whatever has to be done to make it happen. Quickly. Repeatably. Consistently.

So far, Larry has gotten to 2930 FPS with superb accuracy using a 16 twist barrel (and he did it 2 weeks after I dropped the box in the mail...... Like, second range session.) and the goal now is to match the 3200FPS and accuracy that Bjornb achieved (using the breach seater I fabricated for the job) with fixed ammunition.


Personally, I went with a more standard twist rate in my Felix rifle, and I want to see if I can break 3000 FPS with my rifle, and that's why I am watching the HVWST thread and paying close attention to your posts specifically.

There is no "one way" to do this. There are several ways, and I'm not stuck on any of them as being better than another. Some are easier, cheaper, less time consuming, and more forgiving than others (I do think slow twist matches that description better than any other) but there is nothing wrong with any method.

That said, you're welcome to post here, and I think that what you have achieved with alloy development applies to any method regardless of what you are shooting (at least, I sure am hoping so!). Those hard earned results speak for themselves. The fact that you have found a way to push range scrap to the velocities you have, while maintaining some semblance of a group (pretty darn good actually) is nothing short of astounding. I never got that far, and those groups you have posted is why I am back looking at what can be done with your method.
Moreover, you did what you agreed to do when I built you the rifle and I respect that very much.

[cainttype]

Tim, the idea of a totally open discussion about HV from both viewpoints (conducted in a friendly, courteous manner) has proven to be unsustainable. I see no reason why the two different pursuit methods can't be discussed separately, in threads dedicated to each method and the contributor's theories of what works for them, and why.
The discussion of RPM, for example, is welcome here...as are the NON-FACTORY rifles being employed to further the testing of slow-twist/high speed.
Those that don't want RPM theories or slow twist rates discussed are welcome to opt out of those conversations, but those interested in following the tests being carried out by Larry Gibson, Bjornb, and yourself (to name a few) should be able to follow a dedicated thread without the threat of "thread removal" constantly hanging over the discussion because others want to dictate what is allowed to be mentioned.
The standard-twist threads are alive and well. There SHOULD be a safe place to discuss alternative slow-twist ideas without disruptions from people that oppose discussing the concepts.

It's really simple...SHOW us the results of your SLOW-TWIST barrelled "custom" rifles, and feel free to tell us what you're thoughts are...There are dedicated threads for the other camp, so I'm dedicating this thread to NON-STANDARD rifles and different approaches to seek HV with cast using them.
Hopefully Larry will return and post here, as well as Bjornb and yourself. I'm interested in seeing where Larry goes with his 16" twist (30-06 looks inevitable, eventually), as are many others.
Perhaps by dedicating the thread specifically to the pursuit of HV with slow-twist custom rifles, we can have a thread that isn't disrupted by anyone that isn't interested in the progress you guys are making, or the results of the continued testing that we all know is going on with Larry and Bjornb.

[MBTcustom]

Caintype, I couldn't agree more. But I disagree with sensoring another point of view in any form, especially if that person has shown a willingness to post results. People who show a willingness to destroy open discussions and troll people who are earnestly trying to experiment (or in my case, earn a living) shouldn't even be on this board IMHO, and several are gone for that specific reason.
For myself, I have lost too many friends over this issue and I refuse to fight with anyone. The results speak for themselves, and the moderators of this forum are very capable of controlling fights.

[Love Life]

Just post groups, how you did it, and let others think on it as they will.

[cainttype]

Not censoring, Tim, but separating.
There hasn't been any success in combining the two pursuits. We tried that in the ongoing HV thread in the "Cast Boolits" sub-forum. The result is that Larry can't post in the entire sub-forum.
Hopefully by clearly stating the intent of this thread from the beginning, we can accomplish two things without moderator intervention...1) avoid arguing the merits of the two pursuit methods against each other, and 2) provide a tiny spot on this large forum for guys experimenting with slow-twist aftermarket barrels to be able to post freely without confrontational exchanges that result in "moderator intervention".
I fully support the efforts and posts of everyone attempting to help others by providing input and information. Since there are multiple threads discussing cast in "normal" firearms, I see no reason not to have a dedicated thread to "custom" rifles (or even simple rebarrels with slower-than-normal twists).
It may be the only way to explore both methods without the issues that we've all seen develop in the past attempts.

[swheeler]

Not censoring, Tim, but separating.
There hasn't been any success in combining the two pursuits. We tried that in the ongoing HV thread in the "Cast Boolits" sub-forum. The result is that Larry can't post in the entire sub-forum.
Hopefully by clearly stating the intent of this thread from the beginning, we can accomplish two things without moderator intervention...1) avoid arguing the merits of the two pursuit methods against each other, and 2) provide a tiny spot on this large forum for guys experimenting with slow-twist aftermarket barrels to be able to post freely without confrontational exchanges that result in "moderator intervention".
I fully support the efforts and posts of everyone attempting to help others by providing input and information. Since there are multiple threads discussing cast in "normal" firearms, I see no reason not to have a dedicated thread to "custom" rifles (or even simple rebarrels with slower-than-normal twists).
It may be the only way to explore both methods without the issues that we've all seen develop in the past attempts.

Yes this sounds like a very good idea!

[Love Life]

what's the leade time on the barrels?

[cainttype]

Sarge, this thread has been started specifically for posting results you get with your aftermarket barrel. Your results, observations, and personal opinions on the "why" of everything is welcome... Even using the "RPM" term is acceptable, and is as relevent to the discussion as any other insight you feel worthy of discussion.
I hope to have a thread discussing these ongoing slower-than-normal-twist tests by Larry, Bjorn, Tim, you, and any others that remains intact for future referrence by anyone that's interested... LL is bound to be in the thick of it, eventually! ;)

[MBTcustom]

Actually, these are not "slower than normal" twist rates if you step away from the walmart gun rack. There's a reason Shilen keeps barrels in stock in 12 13 14 15 and 17 twist and sells them for $200 each (Shilen is still hanging in there in the top 10 bench rest barrels BTW). Really, why would they do that? They do it because that's what shooters demand. It's commonly known that twist is a two edged sword, and competitors want just enough twist to get the job done, because twisting too fast brings the guarantee that an imperfectly balanced bullet will cost you points if you spin it too fast.

What makes slow twist barrels so perfect for cast, that the cast bullet is denser than a jacketed bullet and is thus shorter weight for weight. Many people do not know that matching twist to the bullet is all about bullet length and speed and has nothing to do with weight. And object of a certain size requires a certain amount of spin to make it stabilize. However, once that projectile (that's everything from a 17 MachII to a football or larger) has reached stabilization, if that projectile has any imbalance in it whatsoever, any additional RPM is going to give centrifugal force something to act on, and eventually, the negative effect of centrifugal force will overcome the positive effect of rotational stability and the projectile will pitch around its axis in flight.

Last year I was at a church function and was enjoying watching the fellers pitch a football back and forth. One feller was quite good at it, and the other sucked rocks. Well I noticed that the feller who wasn't any good threw the ball, it was either pitching end over end, or it was wobbling really bad. Well, I could see the laces on the ball (that's the imbalance that the RPM had to overcome BTW) and I counted the times the laces flashed on the balls surface as it flew across the field to the other guys hands. It was always very consistent. Meanwhile, when the guy who couldn't throw worth beans threw the ball, If the laces were lagging behind the ball would fly end over end. If laces were going too fast, it wouldn't land where he wanted it to. Interesting.

Anywho, that's all about external ballistics, and assuming your bullets are imbalanced, there's an immediate benefit to having a slower twist rate. However, the real benefit happens in the first inch of rifling, because a slower twist rate has straighter rifling that does less damage to the bullet in the first place.

So a slow twist barrel is a double whammy. Make the bullet happy just past the throat, and just past the crown, all the way to the target. Sweet sweet sweet.

What I'm excited about is the possibility that a slow twist barrel is much less alloy sensitive than a fast twist barrel. Most of the XCB testing has been done with Linotype alloy, and #2, but I dipped my big toe in my "house alloy" this past Sunday, and I was amazed that the bullet impacted in the same group, flew at the same speed, and held the same accuracy as my Linotype bullets did. Very interesting!
I didn't have but 15 of them loaded, 10 of which turned out to be well over the RPM threshold, so I won't bother showing you the "imroved cylinder" groups those ten produced, but the 5 I had loaded at 2300 FPS shot a very nice 1.25" group at 100 yards. That's nothing I want to print in the news or anything because it was not a significant sample size, but you can bet your bippy I'm going to try it again with ten + shot groups.

This thread is horribly devoid of color. Allow me to spruce things up with some pictures of my last range session such as it is.

This is my rifle. I made the stock from native Arkansas black walnut. Hand carved it myself. I made the rest it's sitting on as well, and since this picture was taken, I also made a Picatinny rail. It fits me like a glove, and draws a crowd every time I go to the range. This is my very first bench rest stock, and I named it (respectfully) for our mentor. I call it the Felix rifle.

130423

100 yards. Full case of WC867. NOE XCB bullets cast of Lynotype. 2300 FPS +- 10FPS

First 6 shots cold barrel
130424
20 shots one flier
130427
15 shots 2 fliers
130428

Don't bust on me too bad fellers. I'm a gunsmith, not a target shooter. I don't have the iron trigger finger like Bjorn, Larry, or sgt.mike. LOL!

[dragon813gt]

Nice shooting Tim. I'd say that's more than respectable. There are plenty of us that care about minute of animal accuracy more than minute of angle ;)

[swheeler]

Goodsteel: I would like to say not bad showing and can't wait for your new barrel to be fitted and fired. I do have one question though, it looks like you have extended the bolt stop thumb catch, reason?

[MBTcustom]

Goodsteel: I would like to say not bad showing and can't wait for your new barrel to be fitted and fired. I do have one question though, it looks like you have extended the bolt stop thumb catch, reason?

First of all, it looks kewl.
Second, it can be propped open if I want to load a cartridge on the bolt and insert from the rear.

The original was a 1909 Argentine which as you know wraps up beside the rear receiver ring in the most elegant fashion. Unfortunately, it was in the way of the rear scope mount, and the original owner cut a chunk out of it to make it fit. I didn't like the looks of it, so I ground it flat, grabbed a piece of scrap I had in the rack, and brazed it in place with the intent to cut it off flush with the front of the bolt stop. Well, I was about to cut it, and decided that I really liked the looks of it, so I tried it on the rifle, and noticed that it might just come in handy.
After all, this rifle is loud and proud and could pull it off well. It's just a custom touch.

Heres a top view along with the custom rail I milled for it.
130436
and here's the scope mounted with Tally rings
130437
130443
A few more pictures of the Felix rifle:
130438
130439
130440
130441
130442

And here was my first range session (pretty much the same as the first)
I was getting some horizontal stringing on account of the scope being mounted too far forward, which is why I fabricated the rail.
130444
130445

[MBTcustom]

Being that its a single shot, I'm hoping to collect a bunch of barrels for it in the future in various calibers and twist rates. Beats the heck out of buying a whole new rifle!

BTW, I'm a one rifle guy. Yep. Sure am.
Got one for the truck, one for the house, one for the bench, one for hogs, one for deer, one for squirrels, one for rampaging mastodons (talked to Al Gore and he said there was an ice age coming).
LOL!
I believe in using the right tool for the job. (oops! Last time I said something like that the thread got removed.)

[Bjornb]

My range visit was a bust. The barrel has heavy leading after the 340-round fire forming session with undersized bullets, and I was too ignorant to recognize the signs. Now it's Kroil and Chore Boy time. What is it Larry likes to say? If you want to dance, you gotta pay the band? OK it's my time to pay the band.

What I DID find out was that 44 grains of IMR4895 gives an average MV of 2828 fps in my XCB rifle, that was about 130 fps faster than what QL predicted. 4064 also gives very respectable speed, with 43-45 grains clocking 2600-2750 fps. Wish I could show groups like Tim's, but there's always a next time.

[MBTcustom]

130446

Sarge, I never figured you for a trigger pincher?
LOL!

[Bjornb]

:bigsmyl2:
LOL

Bjornb did you or not try the 4064?

Yes I did. Just got my Chrono chip printed out. The series I saved was 43 grains, 10 shots, Min. 2636 fps, max. 2703, avg. 2684, ES 67, SD 20.2. Accuracy was poor, 2.5 MOA or worse, but so was accuracy with several know and good loads, hence the leading discovery and cease fire. The load will be tried again.

[swheeler]

http://castboolits.gunloads.com/attachment.php?attachmentid=130446&d=1423708799&thumb=1
Looks like you shaved that morning!:-)

[Eutectic]

BTW here I am shooting a old enfield

130446

How's the cut over your right eye Mike?

Eutectic

[Nrut]

Hey Mike,
If I had to rebarrel due the the fact the original barrel was shot out, I would go with a slower twist also..
To my way of thinking it would be silly not to...
I am talking cast bullets here...
For the smaller cal. I like faster twist (1:8) to shoot longer match bullets like the Hornady A-Max and BTHP's..
I do have a few slower twist .22's Hornet and .222 that I plan on shooting cast in if I get the time..
Mostly for plinking and having fun as we have no small game or gophers to shoot where I live..
Anyway good luck with your project!

[Cap'n Morgan]

The barrel has heavy leading after the 340-round fire forming session with undersized bullets

340 rounds fire-formed! That sounds like quite a challenge.

I once wildcatted a 6.5x55 to a 7mm Arch. At one point I got tired of wasting expensive powder and bullets on such a mundane task as fire forming the cases (also, every once in a while the case would stretch at the base, ruining the case) On a whim I decided to try using hydraulic pressure to form the cases. I made a simple closed die, using the chamber reamer, with a reamed "smooth bore" for a couple of inches. The case was filled with water and a slip-fit steel dowel inserted through the bore. A solid whack on the dowel with a one-pound hammer and the case was expanded to fit the inner shape of the die. As a bonus, the primer was ejected in the process ;)

If anyone are interested, I'll whip-up a cut-away drawing to help visualize the principle behind the process.

[cainttype]

340 rounds fire-formed! That sounds like quite a challenge.

I once wildcatted a 6.5x55 to a 7mm Arch. At one point I got tired of wasting expensive powder and bullets on such a mundane task as fire forming the cases (also, every once in a while the case would stretch at the base, ruining the case) On a whim I decided to try using hydraulic pressure to form the cases. I made a simple closed die, using the chamber reamer, with a reamed "smooth bore" for a couple of inches. The case was filled with water and a slip-fit steel dowel inserted through the bore. A solid whack on the dowel with a one-pound hammer and the case was expanded to fit the inner shape of the die. As a bonus, the primer was ejected in the process ;)

If anyone are interested, I'll whip-up a cut-away drawing to help visualize the principle behind the process.


Such a contribution would be appreciated, Cap'n. I'm sure it'll be viewed and copied by some that have never considered hydraulic case-forming as an option.

[Bjornb]

Howdy Cap'n, hvordan står det til?
Like cainttype says, I'd really like to see your contraption. This isn't the last time I'll be forming cases.

[jkpq45]

Is it part of the theory that slower than normal twist should reduce leading? I see some folks are experimenting with a normal alloy and others are using straight lino. What about zinc?

[MBTcustom]

Is it part of the theory that slower than normal twist should reduce leading? I see some folks are experimenting with a normal alloy and others are using straight lino. What about zinc?

Leading is a result of gas cutting around the bullet somehow due to an undersized bullet, or a sub standard barrel. Leading almost never happens if your barrel is of excellent quality and your bullets are large enough to create a good gas seal, and we have both as a matter of course.

It is a misconception that a leaded bore is the leading cause of cast bullet inaccuracy. If you are experiencing leading, you need to take a few steps back and reexamine your entire setup. Leading can typically be cured immediately by just slugging your barrel and sizing your bullets .0015-.002 over that diameter. The next challenge is to achieve accuracy, which can typically be done by simply fallowing the recommendations on this forum regarding lube and alloy (just use White Label 2500 or 2700, and add a bit of tin to your COWW to ballance the tin/antimony relationship, buy Lyman #2, or buy Linotype alloy).
Once all of that has been taken care of, you can start pushing your speed up. If you determine the twist of your barrel, you will find (following the advice above) that you will have extreme difficulty going faster than 140,000 RPM or
1361 with a 7 twist
1555 with a 8 twist
1750 with a 9 twist
1944 with a 10 twist
2139 with a 11 twist
2333 with a 12 twist
2722 with a 14 twist

etc etc etc........

If you want the exact RPM you are shooting at, just take your chronographed speed and multiply it by 720, then divide by your twist rate.
So say you see your chronograph reads 1895 FPS and you know you are shooting a rifle twisted 1-12.
1895 FPS X 720 = 1,364,400
1,364,400 divided by 12 = 113,700 RPM.

Once you cross 120,000 RPM, and before you get to 140,000 RPM, you're accuracy is going to fall apart. Violently. (Like, your subMOA to 3" groups suddenly start missing the target backer completely). You have just crossed the RPMTH for your particular gun, load, bullet, alloy, powder selection etc etc etc. If you fell apart at 120,000 RPM you know you either have a janky barrel, you need to try a bullet design that fits your rifle better, or you are using the wrong powder for the job.
If your groups go crazy near 140,000RPM, then you know you have a good rifle, a good load, and a good bullet design. If this is the case, then you can start trying to push things up past 140,000RPM, but the problem with that is that you may not have linear expansion even though you have accuracy at 100 yards. What this means is that you can't depend on your 1" groups at 100 yards to be 2" groups at 200 yards, and 3" groups at 300 yards etc etc etc. You might actually have 5" groups at 200, and at 300, half you bullets miss the target completely!
You have to maintain a linear cone of fire if you expect to have usable accuracy at long range, and you'd really like to be able to do it more than once if you expect to be able to place a humane shot on a dear at 300 yards. Its got to be consistent, or it's useless for hunting deer sized animals at long range which is the ultimate goal of this whole exercise.

That said, as long as you maintain reliable linear expansion, then by all means keep pushing faster! Just realize that linear expansion rarely happens past 140,000 RPM without a LOT of trial and error. It may take as many as 2000 shots to find a combination that will deliver all these results.
That's why I and the people in this thread, are exploring the slow twist barrel solution. It has been talked about for years, but very few have actually embraced and explored it to see just what the possibilities are.
The same goes for perfectly fitting bullets that are what I call "pre-slumped". It's been talked about again and again and again on this forum, but when I look at the bullet designed, very few actually did it (one guy that did is Ranch Dog. Almost all his designes are home runs as far as FIT is concerned) so I did. I made a bunch of phone calls to people I respect, and got input on the design, and put it together into the 30 caliber XCB bullet (along with Larry Gibson and Al Nelson) and so far it's been a rave success for shooting HV in almost any 30 caliber.
Another bullet design that has proven to be very useful is the Lyman 311466.

[dtknowles]

I am not going to repost Tim's post but I am going to take exception to or expand on some of what he said.

First regarding leading, you still get gas cutting and blow by with a bullet bigger than bore diameter. The bearing side of the rifling can abrade the bullet in the groove causing a gap in the lagging side of the groove where gas can blow by and cause gas cutting leading. Some might call this stripping but to me stripping is more serious and is actually cutting chunks of lead off the bullet by the rifling. Stripping and abrading are usually corrected by reducing the velocity or changing the alloy or temper.

I have had good results with lubes other than those Tim recommended (MML+ and 50/50) I am going to test more lubes and maybe get better results. I think it is short sighted to limit the alloy options to those mentioned and think that heat treating or water dropping low sn and sb alloys could work for many shooters.


Bullet design does matter a lot but I don't have enough experience to comment on what works and what doesn't. XCB bullet seems good in my gun.

Hunting deer with a pointed 30 caliber Linotype bullet does not seem to me to be a good choice, in many cases it will act like a FMJ.

He does not address neck tension and bullet jump to the lands which I think are critical to shooting cast bullets accurately. I get my best groups with light neck tension and the bullets jammed into the lead. This may not work for repeating rifles, it certainly will not work for tube magazines.

I am not saying that Tim is wrong, what works for one gun may not work for another and more than one approach might work for some guns. The rpm thresholds and not limits they are guidance, just know they are there and work with them and recognize when the problems you are having are rpm related.

Tim

[onceabull]

Taking the last two posts above into account,is it not reasonable to expect that a properly fitted boolit from an old Lyman 311407(or modern custom maker equiv) would come close ,if not equal a 311466.at "high "velocity for hunting purposes..as of now I haven't seen a need to go beyond 2000 fps in 30/30 or 300 Savage,which is ,obviously no challenge to the rpm "barrier"...I do now own a 26" TC Encore in 300 Win Mag. so may do something on my own to see what personal limitations are..

[btroj]

Once you cross 120,000 RPM, and before you get to 140,000 RPM, you're accuracy is going to fall apart. Violently. (Like, your subMOA to 3" groups suddenly start missing the target backer completely). You have just crossed the RPMTH for your particular gun, load, bullet, alloy, powder selection etc etc etc. If you fell apart at 120,000 RPM you know you either have a janky barrel, you need to try a bullet design that fits your rifle better, or you are using the wrong powder for the job.

Really? This is like falling off the edge of the Earth? Wow, good thing I traveled with Columbus and know better. I am hitting an 8 1/2 X 11 inch target quite easily 100% of the time at 165,000 rpm.

If your groups go crazy near 140,000RPM, then you know you have a good rifle, a good load, and a good bullet design. If this is the case, then you can start trying to push things up past 140,000RPM, but the problem with that is that you may not have linear expansion even though you have accuracy at 100 yards. What this means is that you can't depend on your 1" groups at 100 yards to be 2" groups at 200 yards, and 3" groups at 300 yards etc etc etc. You might actually have 5" groups at 200, and at 300, half you bullets miss the target completely!

How do we KNOW that accuracy is linear? Get a copy of the book "Precision Shooting at 1,000 Yards" and look at page 15 in the second printing. An interview with Tom Whitaker. Don't know who that is? Might look him up, he knows an awful lot about shooting in general but especially at long range. But I digress, back to the topic at hand.
"Finally, I do not believe that accuracy is a linear function. I think it's hyperbolic. Specifically, just because a rifle may group .5 MOA at 100 yards doesn't mean it's a .5MOA rifle at 1,000 yards. I have owned and have seen rifles (.308's) that shoot great to 800 yards, pretty good at 900, but you couldn't hit your butt with them at 1,000 yards. You HAVE to test the rifle at the distance you are going to be shooting at to be sure it will work."

That said, as long as you maintain reliable linear expansion, then by all means keep pushing faster! Just realize that linear expansion rarely happens past 140,000 RPM without a LOT of trial and error. It may take as many as 2000 shots to find a combination that will deliver all these results.

What? Shoot 2000 shots just to learn something? What a waste of lead, primers, powder, and time. Seems to me someone likes to say that it is cheaper to screw on a new barrel than to shoot 2000 shots.

That said. Yes, it may well be easier to shoot at high velocity with a slow twist barrel. I just hate this constant mention of the rpm threshold in situations like this. You make it sound almost impossible to exceed 140,000 rpm and hit the paper. What claptrap. I have posted targets on this forum that show what I have done at well over that "threshold". While it may not be as easy it is most certainly POSSIBLE.

It did not actually take me a LOT of trial and error. I used a single alloy, a single bullet design, and only 2 powders. I have about 500 rounds total thru the barrel and some of those were for sighting in and a test run with 50 rounds of jacketed. Not a LOT of work, simply looking at the problem in an appropriate way and asking questions. I tried a powder, found it too slow and tried another. That powder, RE15, has given me decent groups. I am hardly satisfied with where I am today with the project but I have more plans in the works and have complete confidence that it is very possible to get MOA groups at 100 yards at well over 140,000 RPM.

In reality I have noticed a single problem with the rifle at this sort or velocity with a 171 gr bullet. Barrel torque pulls the rifle pretty hard on the bags.

[btroj]

LV

100 yds.
5
5
0.1599"
Bill Goad
8/13/08


LV
100 Meters
5
5
0.1898 (0.1735)
John Brown
8/28/02


LV
200 yds.
5
5
0.1652
Wayne Campbell
8/20/04


LV
200 Meters
5
5
0.2053 (0.1876)
Jack Neary
8/29/02


LV
300 yds.
5
5
0.1937
Bill Sutton
7/30/00


LV
300 Meters
5
5
0.5527 (0.5054)
Tom Seitz
6/22/68


This is taken from the IBS records page. The record group in MOA is .1599 at 100 yards, .1652 at 200 yards, and .1937 at 300 yards. The 300 yards record is 21% LARGER than the 100 yard record and 17 percent larger than the 200 yard record.

These guys take this all pretty dang seriously and if they can't get "linear accuracy" then why would I expect to?

[dtknowles]

In reality I have noticed a single problem with the rifle at this sort or velocity with a 171 gr bullet. Barrel torque pulls the rifle pretty hard on the bags.

This is the problem I have with the XCB bullet and is the reason I have been holding off on buying the mould. I really want a lighter bullet, I can't get that bullet to more than 2600 fps in my 30 BR and at 2400 fps it already kicks to much for shooting free recoil.

Tim

[btroj]

Mine isn't the direct recoil, it is the barrel torque pulling the rifle to the side.

But yes, a lighter bullet would be nice. Something around 150 grains. It would change the powder choices into a realm with a potentially wider selection.

[MBTcustom]

LV
100 yds.
5
5
0.1599"
Bill Goad
8/13/08


LV
100 Meters
5
5
0.1898 (0.1735)
John Brown
8/28/02


LV
200 yds.
5
5
0.1652
Wayne Campbell
8/20/04


LV
200 Meters
5
5
0.2053 (0.1876)
Jack Neary
8/29/02


LV
300 yds.
5
5
0.1937
Bill Sutton
7/30/00


LV
300 Meters
5
5
0.5527 (0.5054)
Tom Seitz
6/22/68


This is taken from the IBS records page. The record group in MOA is .1599 at 100 yards, .1652 at 200 yards, and .1937 at 300 yards. The 300 yards record is 21% LARGER than the 100 yard record and 17 percent larger than the 200 yard record.

These guys take this all pretty dang seriously and if they can't get "linear accuracy" then why would I expect to?

I hear what you're saying Brad, but that's not quite what I'm talking about. I'm not talking about 21% larger cone of fire. I'm talking about much more than that. Those results show bullets that are still very much under control, and I would still consider that usable accuracy. (boy that's the understatement of the year!)
but there's a big difference between that, and spraying the berm at 300 ya know?
Maybe this spring you will have a chance to test your HV loads at 200 or even 300? I'm really interested to see what you get. (if that sounds snarky, I don't mean it that way. I really am very interested.)

Oh, and on the subject of barrel torque, that's why I designed the Felix rifle forend the way I did: Low, broad, and heavy. Sucker rides the bags like Santa's sleigh.

[dtknowles]

LV

100 yds.

5

5

0.1599"

Bill Goad

8/13/08



LV

100 Meters

5

5

0.1898 (0.1735)

John Brown

8/28/02



LV

200 yds.

5

5

0.1652

Wayne Campbell

8/20/04



LV

200 Meters

5

5

0.2053 (0.1876)

Jack Neary

8/29/02



LV

300 yds.

5

5

0.1937

Bill Sutton

7/30/00



LV

300 Meters

5

5

0.5527 (0.5054)

Tom Seitz

6/22/68



This is taken from the IBS records page. The record group in MOA is .1599 at 100 yards, .1652 at 200 yards, and .1937 at 300 yards. The 300 yards record is 21% LARGER than the 100 yard record and 17 percent larger than the 200 yard record.

These guys take this all pretty dang seriously and if they can't get "linear accuracy" then why would I expect to?

If you go back to Larry's original posts early in the XCB development his definition of linear accuracy made allowance for the kinds of no linear expansion you show in this post. Many secondary factors are non-linear.

The long range .308 win problem you posted might be related to the fact that it is hard to keep that round supersonic all the way to 1000 yards. The transonic buffet is clearly a nonlinear effect.

Tim

[btroj]

If Tom Whitaker mentions it I can guarantee he isn't speaking of transonic problems. He is an accomplished LR shooter and he didn't mention transonic issues, I'm sure he would have if that was what he was speaking of.

[Love Life]

I don't have the book, but was Mr. Whitaker shooting jacketed?

[btroj]

I hear what you're saying Brad, but that's not quite what I'm talking about. I'm not talking about 21% larger cone of fire. I'm talking about much more than that. Those results show bullets that are still very much under control, and I would still consider that usable accuracy. (boy that's the understatement of the year!)
but there's a big difference between that, and spraying the berm at 300 ya know?
Maybe this spring you will have a chance to test your HV loads at 200 or even 300? I'm really interested to see what you get. (if that sounds snarky, I don't mean it that way. I really am very interested.)

Oh, and on the subject of barrel torque, that's why I designed the Felix rifle forend the way I did: Low, broad, and heavy. Sucker rides the bags like Santa's sleigh.

If your groups go crazy near 140,000RPM, then you know you have a good rifle, a good load, and a good bullet design. If this is the case, then you can start trying to push things up past 140,000RPM, but the problem with that is that you may not have linear expansion even though you have accuracy at 100 yards. What this means is that you can't depend on your 1" groups at 100 yards to be 2" groups at 200 yards, and 3" groups at 300 yards etc etc etc. You might actually have 5" groups at 200, and at 300, half you bullets miss the target completely!
You have to maintain a linear cone of fire if you expect to have usable accuracy at long range, and you'd really like to be able to do it more than once if you expect to be able to place a humane shot on a dear at 300 yards. Its got to be consistent, or it's useless for hunting deer sized animals at long range which is the ultimate goal of this whole exercise.

You mention linear accuracy and then explain it as 1" at 100, 2" at 200, 3" at 300. Your words, not mine.

Post 4 in this thread.

Right now, we are trying to see how fast a bullet can really go. In this thread twist doesn't matter. The fellers are not limiting themselves to certain twists, certain weight classes, certain bullets, certain lubes etc etc etc. It's all about speed, and do whatever has to be done to make it happen. Quickly. Repeatably. Consistently.


This sounds like what the "goal" has been all along. Push the envelope. See what is possible. I agree with that. What I have an issue with is this.

Its got to be consistent, or it's useless for hunting deer sized animals at long range which is the ultimate goal of this whole exercise.

If the ultimate goal in long range deer hunting then you will be quite disappointed with a hard, non-expanding pointed bullet. You may as well be hunting deer at 300 yards with an FMJ as to use a linotype bullet with a pointed nose.

What IS the "goal"? Mine is to see what I can do. I want to expand MY horizons in shooting. I want to become a better caster and shooter.

[dtknowles]

Mine isn't the direct recoil, it is the barrel torque pulling the rifle to the side.

But yes, a lighter bullet would be nice. Something around 150 grains. It would change the powder choices into a realm with a potentially wider selection.

I understood what you meant about torque, it increases with increased recoil and would be less with a lighter bullet at the same velocity.

I find that shooting free recoil does not work if the recoil is very light or too heavy and if really heavy it hurts. Bag friction can play into this. My front bag actually clamps the stock to keep the gun from torqueing.

I was surprised that the XCB would stabilize in my 16 twist barrel but at 2400 it seemed stable and should only be better at higher velocity.



130581

Tim

[MBTcustom]

If Tom Whitaker mentions it I can guarantee he isn't speaking of transonic problems. He is an accomplished LR shooter and he didn't mention transonic issues, I'm sure he would have if that was what he was speaking of.

Yeah, but
A. that's jacketed bullets at HV and long range and we are talking about cast bullets at short range going just barely that fast.
B. You're talking about typical load gyrations, and I'm talking about a sudden collapse of anything that could be called even remotely accurate.

You can't prove HV using jacketed research and prove accuracy using low velocity cast bullet research. That's picking the parts you want and ignoring the rest.
Very few examples of any kind are available for reference in regards to high velocity (being 2500 FPS or greater) with accuracy using cast lead bullets, anywhere close to the results you posted up yonder.

Besides, who cares? You're manipulating alloy to accomplish your HV goals. That's your passion and pursuit, and I give you full props for it. I'm manipulating the twist of the barrel to accomplish my HV goals and it makes you angry. Why is that?
I'm committed to bringing every trick in the book to full explanation, without trodding on anyone else's pursuit. I'm not trying to start any fights, I'm just trying to learn.
The slow twist method works pretty well despite all the bad press it brings, and I just want to post the results in peace.

[btroj]

I don't have the book, but was Mr. Whitaker shooting jacketed?

I am quite certain he was. He was speaking in the context of competitive LR shooting. If he mentions the 308 cartridge, and he does, I bet he is speaking specifically of Palma shooting. Either way, the guy knows his shooting. He has been chosen as Captain of the US Veterans Team for the US Palma Team.

Shooting cast I would expect to find accuracy to be LESS linear as we are shooting a flat based bullet and by 300 yards the wind drift will become a greater factor than with an HPBT. Our bullets just don't have the long range legs of a good jacketed bullet.

[MBTcustom]

I understood what you meant about torque, it increases with increased recoil and would be less with a lighter bullet at the same velocity.

I find that shooting free recoil does not work if the recoil is very light or too heavy and if really heavy it hurts. Bag friction can play into this. My front bag actually clamps the stock to keep the gun from torqueing.

I was surprised that the XCB would stabilize in my 16 twist barrel but at 2400 it seemed stable and should only be better at higher velocity.



130581

Tim

That's a phenomenon that has piqued my interest quite a bit as well. The cast bullets are denser/shorter than jacketed which automatically puts you in a slower ideal twist rate, but I saw CBA match results where people were shooting really great groups at less than 2000 FPS with 17 twists!!! that's just nutty! They shouldn't stabilize at that low a twist, but people are WINNING with setups like that.
Anybody have an idea of why that is, I'm all ears.
Regardless, that gives us a whole lot of latitude with these slow twist experiments.
BTW, my front rest clamps in a similar way, and it sure makes things nice. This is my first venture into a bench rest style rifle, and it rocks!

[Larry Gibson]

Excellent down and dirty dissertation goodsteel. So to further understand why we want to control the RPM to be able to shoot cast bullets at higher and higher velocity accurately (preferably to the same velocity level as the cartridge will shoot an equal weight jacketed bullet) we need to understand exactly what it is that cause the loss of accuracy within such a span of RPM. I have gone to great lengths on numerous threads for a lot of years on this forum explaining the cause and why there is an RPM Threshold. A quick read (well maybe not so quick) of the following threads will give you the idea.

http://castboolits.gunloads.com/showthread.php?245302-RPM-Threshold-A-Tale-of-Three-Twists-Chapter-II (http://castboolits.gunloads.com/showthread.php?245302-RPM-Threshold-A-Tale-of-Three-Twists-Chapter-II)

http://castboolits.gunloads.com/showthread.php?208186-RPM-Threshold-barrel-twist-velocity-chart (http://castboolits.gunloads.com/showthread.php?208186-RPM-Threshold-barrel-twist-velocity-chart)

However, in this post, my first post in this thread, I want to give you another ballistician’s explanation. I have mentioned his name before and at his request I will quote him chapter and verse from his very fine book; APPLIED BALLISTICS FOR LONG-RANGE SHOOTING, 2nd ed.

So let’s take a look at what Bryan Litz says in his very fine book that relates to this thread: Chapter 10, Bullet Stability, page 144;

“The relationship between stability and precision [what we generally refer to as “accuracy”or group size] is probably where the bulk of stability misconceptions exist. Gyroscopic stability can affect precision in two ways. First if the bullet is not adequately stabilized, it will emerge from the muzzle and fly with some significant amount of yaw until it stabilizes (goes to sleep). This situation is bad for precision and adds significantly to the bullets drag. This problem can be simply solved by choosing a proper twist rate.
It’s also possible for precision to be compromised if the bullet is spinning faster than it has to be for adequate stability. When a bullet emerges from the muzzle of a rifle, it’s spinning very fast. Any imperfection in the shape,balance or alignment of the bullet will cause it to disperse away from the bore line when it exits the muzzle. The amount of dispersion is related to how severe the imperfections in the bullet are, and also how fast the bullet is spinning. Higher spin rates produce more dispersion. This situation can create the illusion that the bullet’s dispersion is caused by excessive stability, but that’s not the reality. The actual stability level ofthe bullet is not what causes the dispersion! The imperfections in the bullet cause dispersion, and the dispersion is increased the faster the bullet is spinning. The more balanced the bullet the bullets are, the less dispersion will result from spinning them faster. One ofthe reasons why short range Benchrest shooters choose to shoot short, blunt, flat based bullets is because they require such a slow twist to stabilize. The slower twist barrels aggravate the imperfections of the bullets much less than faster twist barrels and smaller groups result.
The relationship between spin rate and dispersion is stronger for low quality bullets. This is why BritishCommonwealth ‘Target Rifle’ shooters long used 1:14” twist barrels as until recently the discipline’s rules required the use of ‘as issued’ 7.62mm NATO military ammunition which was loaded with relatively poor quality 145 grain FMJBT bullets. As precision bullet manufacturing technology matures and the resulting products move ever closer to having perfect balance,the relationship between spin rate and dispersion is diminishing.
There is much debate about what barrel twist rate or bullet RPM is optimal for precision shooting. The answer isn’t as complicated as it’s made out to be. The right way to choose the proper twist rate for a particular bullet is to select a twist that for a particular bullet is to select a twist that results in a stability factor (Sg) of at least 1.4 [Miller Stability Formula] at your intended velocity. If the stabilityfactor is a little higher, that’s ok. The effects of over spinning a bullet are not nearly as bad as under spinning it. If the Sg is up near 2.0, that’s not necessarily bad. As long as you’re shooting good bullets there will be no detectable difference in precision. If you get a batch of bad bullets, a slower twist barrel may be more forgiving, but the difference would be hard to resolve.”

Whew….sure is a lot of information in there! However, notice any similarity to what I have been saying? Now to be fair to Bryan Litz his very fine book is not about cast bullets. As a matter of fact he does not mention cast bullets at all. His book focuses on the best of match grade jacketed bullets made by several manufacturers. That does not mean the same Laws of Physics and Ballistics do not apply, they indeed do apply to cast bullets just the same as jacketed bullets. It’s just harder for us to cast, let alone launch, cast bullets with any where near the “goodbullets” that he refers to as Bergers, Sierra’s and Hornady’s are his primary choice of bullets.

So what does it mean? Mr. Litz says we should choose the correct twist for the bullet and velocity we want keeping the Miller Formula Sg Factor above 1.4 (stability) and under 2.0. Let’s say we want to use the 30 XCB with a weight of 165 gr and a length of .985” at 2500 fps minimum. The SG factors for the following twists are;

10” twist; 4.31 Sg
12” twist; 2.99 Sg
13” twist; 2.55 Sg
14” twist; 2.20 Sg
15” twist; 1.92 Sg
16” twist; 1.68 Sg
17” twist; 1.79 Sg
18” twist; 1.33 Sg

[btroj]

You can't prove HV using jacketed research and prove accuracy using low velocity cast bullet research. That's picking the parts you want and ignoring the rest.

Interesting. The entire rpm theory is based on Brian Litz and his work. Did Mr Litz do his work with cast bullets? Was he speaking of 100 to300 yards?

What parts are you picking and what are you ignoring?

I'm committed to bringing every trick in the book to full explanation, without trodding on anyone else's pursuit. I'm not trying to start any fights, I'm just trying to learn.

Then stop commenting about how I am wasting my time and money by shooting 1500 to 2000 rounds to learn. You brought rpm into this. You talk about it as if the bullet suddenly turns 90 degrees at 100 yards if the rpms exceed a magic number.

This isn't rocket science. It is a simple matter of casting bullets, loading them and shooting them. See what the results are. My results, so far, stand for them self.

I too would love to be able to just shoot and enjoy myself. What I don't like is the fact that any discussion about HV accuracy involving you turns almost instantly to rpm theory. That dog don't hunt.

[Larry Gibson]

From that we can see why it is extremely difficult toattain accuracy at 2500 fps from the 10 and 12” twist barrels.The bullets are just spinning to fast whichcreates a lot more centrifugal force and that is the basis of the RPMThreshold.With the 12” twist if we doeverything just right and can get a fairly decent cast bullet launched with fewimperfections we know we can get 1 – 1.5 moa at 2500 fps.You can see where I did that on the NOE Forumthread on the 10 and 12” twist thread.

We kind of skipped over the 13” twist although there arenumerous Palma rifles and barrels of that twist available.The 13.5” twist seems to also be gaining infavor for Palma rifles but they are using 1st class quality jacketedbullets.Yet both should do well withthe XCP bullet in the 2500 – 2600 fps range as we can see the Sg is lowering.

Now, we have a lot of experience with the 14” twistbarrels in several 30 XCB rifles and my own Palma .308W.Given a longer barrel, slower burning powdersand quality cast XCB bullets we are seeing excellent and repeatable accuracy inthe 2600 – 2700 fps range.We see the 14”twist’s Sg Factor is getting down where Mr. Litz says it needs to be.A lot of practical shooting at 100, 200 and300 yards with 10 shot groups is proving him correct.

The 15” twist is looking better with the 1.92 SG (underthe level Mr. Litz recommends) and it should do well but I’ve no knowledge ofanyone who has one of one in the pipeline.My new rifle “Dawn” has a 31” Broughton 3 groove barrel with a 16”twist. Given my experience (I’ll mentionmore of it along the way in this thread) with the 14” twist in my 27.6”barreled .308W Palma rifle I felt there just wasn’t enough case capacity toreach the initial goal of 2800 – 2900 fps with the 30 XCB bullet.Thus I had goodsteel install the Broughtonbarrel on a very fine BRNO VZ24 action and chamber it to the 30x60 XCBcartridge which has about 5 – 6 gr of powder larger capacity than the 30 XCB(30x57 which has essentially the same capacity as the .308W).Goodsteel work his usual magic and added afew very much appreciated touches.Goodsteel does excellent work by the way and I highly recommend hiswork.

The 16” twist has an Sg Factor of 1.68 which is very goodaccording to Mr. Litz.Again practical shootinghas proven him correct as the pictured groups were shot with the 30 XCB bulletcast of #2 alloy and WQ’d.The leftgroup was with bullets sized .3105, the middle with the bullets sized at .309and the right group the bullets at .309.Note this was also while fire forming the cases.Velocity ran 2932 fps for the 1stgroup, 2920 fps for the middle group and 2928 fps for the last group.The internals of SD & ES for bothvelocity and psi were larger with the smaller more sized bullet.Obviously the .3105 sizing (basically ascast) is Dawn’s favorite.Both shots lowout of the group in the 1st target were called by me; they were the5th and 10thshots!I justcouldn’t handle the pressure I guess………

Well enough discussion for now as I’ll be going to therange tomorrow to test the XCB bullet over LvR powder and fire form a secondhundred cases with the LBT 150 gr bullet over 4895.I’ll be posting more results here and over onthe NOE forum.Hold hard and shootstraight……..

Larry Gibson

130582130585130584130583

[btroj]

Yeah, but
A. that's jacketed bullets at HV and long range and we are talking about cast bullets at short range going just barely that fast.

Larry, all that good work by Brian doesn't matter, just ask Tim.

The effects of over spinning a bullet are not nearly as bad as under spinningit.If the Sg is up near 2.0, that’s notnecessarily bad.As long as you’reshooting good bullets there will be no detectable difference in precision.If you get a batch of bad bullets, a slowertwist barrel may be more forgiving, but the difference would be hard toresolve.”

Ok Larry, looking at the above quote from your post lets see. IF you get a bad batch of bullets a slower twist MAY be more forgiving, but the difference would be hard to resolve. MAY be more forgiving. Hard to resolve.

Yes, he says those are the "ideal" twist rates but he doesn't say much about going over other than that with bad bullets a slower twist MAY be more forgiving yet it would be hard to resolve the difference.

How do you extrapolate that to mean a cast bullet can't go over a certain rpm with any sort of accuracy? I have a feeling that when he says "hard to resolve" he means it just isn't going to show much on target. For a guy like himself who understands how 1/4 in at 600 yards can cost you a match I bet he wouldn't say "hard to resolve" if it was readily apparent on target.

[Larry Gibson]

Btroj

Get real. Linear dispersion is measured with the same rifle, the same load, the same shooter, the same day in as close to the same conditions and shot consecutively at different ranges. Your showing different rifles , different shooters, different loads (maybe even calibers/cartridges) shot in different years in different conditions. It's apples and oranges. Be nice if you'd not bring this kind of ......let me be nice....."discussion" here. We've been all through this before. You don't want to hear about RPM then by all means quit reading about it. It's that simple. However, if you'd really like to shoot your 30" rebarreled (a Kreiger barrel I believe?) 12" twist XCB you might stick around and pay attention instead of instigating the same old garbage. Let us have our discussion, you don't like it stay out of it......not too hard to figure out.......like your teacher probably told you; if you can't say anything constructive then don't say anything at all.

How do you extrapolate that to mean a cast bullet can't go over a certain rpm with any sort of accuracy?

I don't have to extrapolate it, it has been proven over and over again. And I am not about to go into it with you here.

Larry Gibson

[btroj]

What is the standard for linear accuracy? Can a 2 inch 100 yard group expand to 5 inches at 200 and 8 inches at 300? What are the hard numbers? You throw this around continually but don't give hard numbers.

[MBTcustom]

You can't prove HV using jacketed research and prove accuracy using low velocity cast bullet research. That's picking the parts you want and ignoring the rest.

Interesting. The entire rpm theory is based on Brian Litz and his work. Did Mr Litz do his work with cast bullets? Was he speaking of 100 to300 yards?

What parts are you picking and what are you ignoring?

I'm committed to bringing every trick in the book to full explanation, without trodding on anyone else's pursuit. I'm not trying to start any fights, I'm just trying to learn.

Then stop commenting about how I am wasting my time and money by shooting 1500 to 2000 rounds to learn. You brought rpm into this. You talk about it as if the bullet suddenly turns 90 degrees at 100 yards if the rpms exceed a magic number.

This isn't rocket science. It is a simple matter of casting bullets, loading them and shooting them. See what the results are. My results, so far, stand for them self.

I too would love to be able to just shoot and enjoy myself. What I don't like is the fact that any discussion about HV accuracy involving you turns almost instantly to rpm theory. That dog don't hunt.

Brad, First, I never once said you were wasting your time and money. That is obviously not the case, and I gave you full props for the results you have achieved. The fact that every discussion about HV turns to RPM theory? Well first, I had many discussions with you and others before I ever started pursuing this method (in fact, before I even knew what it was). The fact is that you, and several others would not stop talking about it, and all the evils that it represents, and about Larry Gibson, etc etc etc, that I went to see just how bad this guy really is and I did the unthinkable: I read the RPMTH sticky. Completely through. Without bias (I was a dyed in the wool HVWST shooter till that point). Everything that Larry said matched my experience to a T. No exceptions. Like a perfect puzzle piece. Fact is, I never would have read the sticky if it weren't for you guys talking about it all the time (this is the hand on the Bible truth).
Second, This thread is dedicated to the RPMTH and slow twist barrels. It's in the title. Were not talking about something illegal here. Just a different way to manipulate the bullet.
Third, why does it concern you how I shoot, or what twist barrel I screw on my rifle? Why can't we let the groups speak for themselves and have a good laugh about it when the truth is fully found out about the advantages and limitations of both methods? Why could we not combine the two methods?!?!? What if I find what I'm looking for with slow twist barrels and start shooting 50/50 alloy using the tricks you demonstrate?

[geargnasher]

The only thing proven over and over again is most people can't figure out how to get a balanced cast bullet out of a barrel at over 140K rpm. That should not be construed to mean or prove anything beyond that simple fact.

Gear