RPM Threshold barrel twist/velocity chart

[Nrut]

357maximum is way to kind.

My rifle is a CMP Greek return Remington made 03A3 produced in May, 1943; with a brand new (in the wrapper & cosmo'd when I bought it) Remington made July of 1943 two groove replacement barrel. Barrel was installed by Badgeredd. As of this date the barrel has had only 103 rounds fired through it of the following load and no other:

Bullet Design: RCBS 30-180-SP (Late version, bore riding nose)
Actual weight lubed & checked: 190 grains

Cast of an alloy that is: (according to Badgeredd's alloy calculator)

92.35% Pure lead and other trace elements
3.73% Tin
3.5% Antimony
.22% Copper
.20% Arsenic

(Note: This is a copper enhanced alloy, and not the type of alloy that the OP used in the testing he has presented in this thread)

The easy way to mix this alloy is to follow this simple recipe of 8 lbs. Clip On Wheel Weights, 1.5 lbs. of Pure Lead, and .375 lbs. of Rotometals Grade 11 Babbit for a 10 pound pot. Double the amounts for a 20 pound pot and quadruple the amounts for a 40 pound pot, etc. Here's a hint, don't assume that your soft range scrap is in fact pure lead that's ok to use in this mix, it probably isn't. Use what this recipe calls for, don't deviate. There are enough variables to deal with in Clip On Wheel Weight alloy as it is. No need to have the other components skewed.

Bullets were water dropped from the mold into a five gallon water bucket. They were allowed to stabilize for two weeks, BHN was 28, sized/checked to .310" diameter and lubed with MML + 5% Soap. My mold casts a bullet nose that is .302" diameter using the above alloy from my mold.

The load itself is as follows: (loaded and shot as projected in Quickload)

46 grains of IMR-3031

CCI #200 Large Rifle Primer

54,000 psi / 100% powder burn / muzzle pressure = 7,849 psi

5 shot average over the chronograph is 2,510 fps. I was hoping to match the U.S. MkI ball load which was a 175 grn FMJ Spitzer at 2,600 fps. However, given the accuracy potential this load is showing I'm not going to quibble over 90 fps, especially since my boolit is 15 grains heavier.

Ok, so here's the deal with this rifle and load. When I say 103 rounds I mean that is the absolute total number of rounds which have ever gone down this barrel, period. The barrel has only ever fired this particular load. The 1st round went down the tube at the end of May. First 5 shots fired went into 3" at 100 yards with one flier I believe to be the very first shot opening the group from 2.5" to 3" Either way, that is within acceptable U.S. Ordinance accuracy standards for these rifles as they came off the line at any manufacturer. I was shooting that day with Castboolits Member "Mostlyonthepaper" and he can verify this plus I have the target saved. Minor sight adjustments were made and after that the rifle has not been put through any serious target work since; just pounding rocks and steel at 250 yards. The plan has been to give it about these 100 rounds of shooting for the bore to season with lube before getting serious on paper. While shooting at Badgeredd's place on June 8th the rifle seemed to be shooting better as the round count rose. 357maximum was spotting for me through 10x binoculars and advised I was hitting the same 2"-3" spot on a rock @250 yards repeatedly before I split the thing.

So, the load shows some real promise out of a 24" barreled 03A3 with issue receiver sights. Enough to warrant some real testing.

dtknowles -

Right off the bat I will tell you this. Bullet fit is king. Also, my rifle has a 24" barrel and yours has a 22" barrel. I believe, based on my experience, that keeping muzzle pressures below 8,000 psi is very important for even usable accuracy. Your barrel will produce higher muzzle pressures than mine with the same load due to the fact that it is shorter. Find a bullet in the 200-210 grain weight range when cast out of this alloy that fits your rifle properly when chambered. Start out at 43 grains of 3031 and work up. If you have the alloy, lube, and fit right I think you could find a good load.

Thanks for your write up Matt..
Always interesting to see how you, Mike, Bruce & Edd are approaching the HV with cast puzzle..
I use a lot of information that you all post and I bet others do also..
Wasn't really planning on fooling with HV this summer myself but happen to have a Smith Corona O3A3 (43) similar to yours
It was the first rifle I shot cast out of and did quite well at low velocity back when my eyes where good..
My target was a small black square the same width as the front sight at 100 yards..
Also have a new in the white two groove wrapped in paper with grease..
Naw, think I'll just shot PP when I get to it..
But I will try 3031 thanks to your post..


Cheers

[frnkeore]

For those interested in gain twist barrels and what they can or can't do, contact Ron Smith of RKS barrels in Canada (costs no more to call than the US). He has been making, shooting and selling them for more than 20 years.

The way he got started was buy shooting his barrels in matches and winning. His business has snowballed in the last 10 years.

His number is:

403 631 2405

Tell him, Frank Elliott, in Oregon sent you.

Bartlein is another barrel maker that does gan twist. I believe they started making them about 2 years ago. I don't have the number but, a search will bring it up.

Frank

[Mik]

As a new member on this forum, I can't really see how this became an argument of great proportions.

It seems like a simple scientific fact that an imbalanced, asymmetrical, rotating object will become more and more unstable as it rotates faster and faster. An imbalanced wheel on a car will feel fine at 30mph but not at 70mph.

It also seems like a scientific fact that a PERFECTLY balanced and symmetrical object will NOT be affected by increasing rpms because the forces acting on the object remain exactly equal in opposite directions. I think btroj mentioned that the answer lies in creating more balanced projectiles, I think he is correct.

That being said, contractors for NASA have difficulty manufacturing perfectly balanced objects in their multi million dollar facilities. It would be unreasonable to think a guy melting wheel weights in his garage and pouring them into a $100 mold could manufacture a projectile that will be perfectly balanced and symmetrical after being squeezed through a rifle barrel. (does anyone disagree?)

So, logic says there must be an rpm threshold somewhere, there is no such thing as a perfect projectile. Some might get closer than others, but I can guarantee none are perfect when they emerge from the bore.

Larry presented evidence that suggests that with his manufacturing skill (likely greater than that of many members) and his manufacturing equipment (likely similar to that of many members) his projectiles appear to run into that threshold somewhere within the ballistic capabilities of the .308.

Why the huge fight?

[MBTcustom]

Well, larry, I do think your intent for this thread was to see how RPM affected your ACCURACY with 3 different rifles, with 3 different twist and not just how fast your 14 twist would go. Am I wrong? What does the "tale of 3 twist" mean? The way I read this thread is that you were proving that RPM was the reason that accuracy fell off as velocity increased. Am I wrong again?

I would like to ask you again:

With what we have learned in this thread, do you at least concede that YOUR "threshold" is actually somewhere between 160,000 and 190,000 RPM and not 120,000 to 140,000 RPM or, can larry, never say that he was mistaken?

Frank

Hey Frank, I've read Larry's threads on this subject and and from that brief perusal I would say "it depends".
Why do you keep trying to force him into saying that it's a limit?
If he explains it from the viewpoint of RPM you bust him with FPS. If he explains it from a viewpoint of FPS you bust on him with RPM. It's circular reasoning, and I really don't think you are after any answers here. I think you just want to watch Larry dance, insure thread drift, and basically fill up the thread with anything but useful information.
This is trolling.
Why don't you explain what you have done in your rifle hmmmmm? What have you demonstrated that negates this? (or are you actually doing your shooting the same place you pull your information from....online?)
Seems like anytime anybody asks you to give information about what you have done, it's always somebody else, long ago and far away, but written online. Heck you weren't there, it could have been a typo for all you know but it says something different so that'll work. Is your whole argument based on what you read online? That's really weak man.

All Larry is saying is that with a standard trifecta alloy (that's lead, with a sniff of tin and antimony, any mix you like) each rifle and load will have it's own RPMTH. The only way to be sure what that will be is to shoot it, and work up till accuracy falls off. However, the biggest indicator of approximately where that point is, seems to be able to be determined by twist rate. This thread was about demonstrating that to the masses.

You say it's wrong based on alloy change. OK so what? Most of us are not going to go through the hurtles of mixing copper rich alloy. We want to know what is possible with a trifecta alloy (that's lead, with a sniff of tin and antimony, any mix you like). We all know we can push the RPMTH up to about 300,000RPM just by using standard jacketed bullets. To use that argument to say the RPMTH is bunk is just silly.
I'm willing to listen, and I think Larry is too, if some real, first hand, evidence is brought forth that uses a standard trifecta alloy (that's lead, with a sniff of tin and antimony, any mix you like).

Would you please speak plainly? What have you seen that makes all of this null and void?

Personally, I'm starting to really buy the RPMTH as a window of truth if not the whole picture. I am taking this position based on what my rifles have done.
For instance. I have a type 38 Arisaka. It is barreled with a .307 groove 1-11.25 twist barrel 22" long. It is bluprinted, has a 3lb trigger, bedded with milspec bedding compound, the rings are lapped, and installed correctly. It's chambered in 308 Palma.
With jacketed, it's a one hole rifle. Shoots 168 Hornadys into a 1/2" cloverleaf at 100 yards.
Now, the first time out with that rifle (not having read Larrys RPMTH threads) I had it loaded up to about 2400fps with IMR3031, a duplex load of WC867 (that was actually 2100fps out of this rifle) and 4895. That rifle shot patterns at 50 yards with everything but the duplex load. Very disappointing. I've shot better groups with my shotgun launching round balls out of a smooth 12 bore. A few weeks ago I loaded up some 1800FPS loads with 3031 and shot about 1" at 100 yards.
Now granted, that was just one outing, and I'm not nearly finished with that, but when I read what Larry has written here, it sure gives me pause for thought, and one group from my rifle trumps 1000 pages written online.

[PAT303]

I've got to say I'm with Tim,why don't people simply post up their results in plain English so the rest of us can learn,why try to discredit one another?,why are we all here?,to learn. Pat

[garym1a2]

The huge fight is because many people don;t want to agree with Larry. Even though they know that barrel twist has a huge affect with bullet preformance either jacketed or cast. My cast experance with Rifles is limeted to a Blackout 1:8 at 1700fps and a Rossi .357 at about the same speed. My results where accecptable to me but I am not trying to push the limit with these as their goals are piggie blaster for the Rossi and Short range 3Gun for the Blackout.

With Jacket Rifles I have more experance and see where most of the guns made the twist is wrong for the shooters of them. Back in the early 90's when I was shooting high power I purchased a new Colt Hbar with a 1:7 twist, using UMc I could not get decent groups at 100 yards and was off paper at 300 yards. Yet the same rifle with 69 gr match kings was good enough to shoot a 99 prone at 300 yards once and clean at 200.

Now days most AR's come with 1:7 twist, even the military. Yet the preformance is poor with the 55gr and 62 gr bullets they use. Yet a 1:9 barrel works great with these bullets.

As a new member on this forum, I can't really see how this became an argument of great proportions.

It seems like a simple scientific fact that an imbalanced, asymmetrical, rotating object will become more and more unstable as it rotates faster and faster. An imbalanced wheel on a car will feel fine at 30mph but not at 70mph.

It also seems like a scientific fact that a PERFECTLY balanced and symmetrical object will NOT be affected by increasing rpms because the forces acting on the object remain exactly equal in opposite directions. I think btroj mentioned that the answer lies in creating more balanced projectiles, I think he is correct.

That being said, contractors for NASA have difficulty manufacturing perfectly balanced objects in their multi million dollar facilities. It would be unreasonable to think a guy melting wheel weights in his garage and pouring them into a $100 mold could manufacture a projectile that will be perfectly balanced and symmetrical after being squeezed through a rifle barrel. (does anyone disagree?)

So, logic says there must be an rpm threshold somewhere, there is no such thing as a perfect projectile. Some might get closer than others, but I can guarantee none are perfect when they emerge from the bore.

Larry presented evidence that suggests that with his manufacturing skill (likely greater than that of many members) and his manufacturing equipment (likely similar to that of many members) his projectiles appear to run into that threshold somewhere within the ballistic capabilities of the .308.

Why the huge fight?

[Hamish]

The Bell Curve.

There was a post on page three stating that all results must be comparable using all powders, irregardless of burn rate. Think about that one for a moment. I do not wish to start a fight, or even a discussion, but for me, this seems a patently false assumption.

Painting oneself into a corner and refusing to come out even when shown that the paint is dry is a sad thing to see.

The universe operates under the Bell Curve and shooting, particularly shooting cast, is no exception. IF we had enough resources to test every combination of alloys, lubes, powders, etc., then we could graph the "window" that each combination would work, and work best in.

I see all the variables as overlapping Bell Curves, when the all overlap, it works. When they all overlap in the most favorable range, it works best. When they dont overlap, you get poor results or failure.

I have a hard time understanding the efforts made to nail the work done on this to one variable or another, when it is all the ingredients in the recipe that make the cookie.

Frkeore, I can find nothing in your posts to objectively refute anything that Larry has presented. I do however, perceive a personal animosity and not much more.

[waksupi]

I've been meaning to do some experimenting in the testing area. I want to see if an original poster can open and close a thread at will, to be able to put relevant information into a thread without others interfering with the transfer of information. Naysayers could open their own threads. There have been a lot of electrons senselessly and worthlessly wasted in this thread. Heaven forbid someone should do research and post it.

[Larry Gibson]

Well, larry, I do think your intent for this thread was to see how RPM affected your ACCURACY with 3 different rifles, with 3 different twist and not just how fast your 14 twist would go. Am I wrong? What does the "tale of 3 twist" mean? The way I read this thread is that you were proving that RPM was the reason that accuracy fell off as velocity increased. Am I wrong again?

Yes you are wrong, read the 1st post in this thread; the answer is there.

I would like to ask you again:

With what we have learned in this thread, do you at least concede that YOUR "threshold" is actually somewhere between 160,000 and 190,000 RPM and not 120,000 to 140,000 RPM or, can larry, never say that he was mistaken? Frank

No I will not concede because what you want is based solely on your own opinion. The 120 - 140,000 RPM range for naked cast bullets of ternary alloy was derived from facts. Here is a graph of numerous loads I researched for another who couldn't understand. Notice the range of RPM with the numerous loads from several cartridges and rifles where the accuracy begins to deteriorate. I base it on proven demonstrated facts, not erroneous opinions.

Larry Gibson

Attachment 108976

[popper]

garym1a2 I think you have it right, the Mil purposely reduces the effectiveness of their weapons & the makers copy it. Rotary inertia is 1/12*m*(3*bore^2+length^2) and is a force that tears our poor boolits apart. Out of balance mass just adds an m*delta D^2 component. Rotary inertia is related to rotary velocity (via torque) and related to fps by twist. It is also the component in gyro equations to provide stability. Jackets & PP are just a strong shell to contain the weaker lead. Cu, Ag, S and other additives add strength to Pb by placing 'bumps' in the Pb lattice so it doesn't 'slide' so easily. Sb/Pb as an aggregate of strong/weak metals, similar to concrete.
So to answer several questions: 1)yes there is a RPMTH. 2) It is related to fps by twist. 3) If you want to extend the RPMTH, change the twist or alloy or use jacketed or PP. There is an old southern saying I learned. Some are so ornery they will argue with a stump (or chair).

[MBTcustom]

Larry modified his rifle to a slower twist, and has demonstrated that it works. He has achieved high speed accuracy.
Others chose to modify their alloy to a harder/tougher result and have demonstrated that it works. They also have achieved high speed accuracy.
Some others have chose to modify the surface of their boolits with a jacket of copper, paper, or plastic. They have achieved high speed with accuracy.
Some others have chosen to modify nothing, and they report nothing, they post nothing but hatred for this particular way of achieving these two goals.
I see that it buggs the fire out of some that this method works, and has more explanation and pictures backing it up than all the other methods combined (with the exception of the jacketed guys.)
That's what I don't understand (I am not kidding, I really don't understand it). If the other methods are so incredibly awesome, then why not post a group instead of an emotionally charged challenge to the OP's character? I mean Larry could be a complete feral human being, but that wouldn't change the fact that he did the work and explained his position. If this method works for people (and it does. I'm building their rifles) and they pursue it, why is that thought of as humping someones leg?

[357maximum]

Tim


MULL TH FOLLOWING STATEMENT OVER FOR A BIT:

I own slow twist barrels too.....why you spose that is????


.........and would I admit to it if I was trying to make Larry look like a fool???? Sometimes "easy" is good.....sometimes the "impossible" is fun to reach for also.......sure at times you are gonna swing so hard trying to get to the fence that you spin around and fall flat on your face while others point and laugh.......but......but....occassionally the ball goes over the fence and that is soooo damn sweet that you buy another "regular" rifle just so you can try it again.

I am not a wordsmith...I cannot express myself via the typed word as others here can......I am not a writer....I am not a ballistician.....I am a try it til I get it kinda feller....I spent most of my working life diggin holes/ditches and filling them with a piece of pipe for more reasons than the simple fact that I truly liked the work. I truly am playing Tetris on high speed with one hand tied behind my back.....it is not by choice however.

[dtknowles]

Tim

You had it right before you switched variables to objectives. MY GAWD MAN this place can be like playing Tetris on the super duper advanced setting.

I am a different Tim but I like playing Tetris and have moved up a few levels, keeps you sharp.

I feel no shame in contributing to thread drift now as we are no longer having a technical discussion.

I just bought some copper bearing babbit. I will cast and shoot and post the groups. I can think of all sorts of thresholds I can break. Nobody ever told me what the threshold is for plain base bullets so I will have to find that myself. I will have to find someplace with a 200 yard range in southeast La.

Tim

[frnkeore]

Ok guys,
I feel like the messager that when he brought the truth to the king, was at once marched to the nearest wall and SHOT!

One guy says this:

"Frkeore (his misspelling not mine), I can find nothing in your posts to objectively refute anything that Larry has presented. I do however, perceive a personal animosity and not much more."

After I posted the match results with the rifle and all the loading data with it. For not just one person but three.

Match result data is one of the most reliable sources we have for what is actually true. Every match has approx a minimum of 10 witnesses to a max of 100 or more. If you believe a typo was entered 3 times or more well......... I don't know what to say. Match shooters are very zealous and a try to eleminate as many errors as possible, even with there equipment info.

I take offence to any referance of me being a "keyboard shooter" I have participated in rifle shooting matches (Bullseye pistol for 2 yrs, also) since 1982 and you can find my scores published in ISSA & ASSRA match results!

I am a student of rifle accuracy. I'm not a Master as there is ALWAYS something new to learn.

One thing that I don't understand on this forum, in general, is the lack of interest in what is the only organization that is in business to further the shooting accuracy of GC cast bullets, the CBA (Cast Bullet Assoc.). If you follow the results, posted in the match results, you WILL learn something. What happens at at the matches are FACT!!!! Not opinion.

I think that 357Maxium somed it up, very nicely as follows:

2. Honestly my biggest issue with Larry and his "research" is that (in my opinion) it is basically the same as researching the reason why a 4cylinder Ford tempo will not win the Daytona 500. Larry has set out to prove why mediocre boolits/alloys in mediocre guns are mediocre in performance fps wise...why I do not know...to each their own, but the way he gets fired up when someone tells him a V8 would work better in the Daytona500 leads others to get frustrated.....myself included.

To get the maximum proformance from a jacket or cast bullet rifle, you have to have a well bedded action, good barrel and as I posted earlier, the correct chamber and throating. Only with that will you get the most reliable and best available results.

Whether or not, I choose to shoot high RPM loads is irrelevant, my purpose here is TRUTH and accuracy in reporting Fact!

larry's report here is just that a report of 3 differnt rifles with 3 different barrels and how they shot with his skill level. It's not a scientific test. If his "Palma" rifle was built as a match rifle, it will alway produce more accurate results that the other two. The Palma rifle still isn't capable of the best cast bullet accuracy because the "palma" chamber (if it was cut with a Palma reamer) still doesn't have the optimum throating for cast bullet. It is optimum for the 155 gr Palma match bullet, nothing else.

I would be interested in anyones opinion that does scientific testing, as to how reliable this test would be to prove anything regarding a corralation of barrel twist vs velocity or if they think that "threshold" would be a appropriate term. It does make for a very conviniant term, though.

Put the blind fold on me and fire away

Frank

[Larry Gibson]

You really want to degenerate this thread to such a low level personal attack? I don't.

None of the very few of you "others" who can only come up with personal attacks, in the end, as such have posted anything such as you profess; "I and others simply mention the fact that more is possible and it has been done with the right techniques/materials". If that is true then where are the results? Where are "right techniques/materials"? None of you have posted them. I have continually offered to assist you and the "others". What I've gotten is "Oh I don't have any particular bullet in mind and haven't made a decision on powder so it will take me years and hundreds of trips to the range to figure it out."

So if you and the "others" have it figured out why don't you show us right here right now? Why don't you then tell us how you did it right here right now? Then why don't you teach us how we can do what you and the "others" claim can be done right here right now? Numerous "leg humpers" through out this thread have asked any of you or the "others" to post anything to document what you claim you've done. None of you, not you nor the "others", have posted anything. You and the "others" have cried "wolf" so many times no one believes you anymore.

Since I began this discussing the RPM Threshold on this forum and perhaps on the old one I have proved the RPM Threshold exists. Legions of forum members who have found the RPM Threshold now understand what it is and what causes it. Knowing what the RPM Threshold is I have told them many, many times how to push the RPM threshold up. I have pushed the RPM threshold up and have posted the results on this forum with details in how it was done. I have helped numerous of them to do the same, I have offered continuously how they can do it also.

All you and the "others" have offered anyone is ".......more is possible.....if you want it......". Yet you offer nothing. I will give you credit with your admission of "......that's all I am ever trying to point out in this type of thread......" because that "point" is all you and the "others" make. You show nothing, you teach nothing. And now you have the unmitigated gall to call the rest of the forum members "leg humpers".

If you don't like the "drama" don't go to the play.
Doesn't matter what I think What matters is what all the forum members now think............

Might be wise if a moderator locks up this thread before it really get out of hand?

Larry Gibson

[Larry Gibson]

frnkeore

Why should we shoot you, you continually shoot yourself........mostly in the foot..........

Larry Gibson

[MBTcustom]

I expected you would ask for a blindfold.
Typical.