Traditional Muzzleloading Association

Shooting Traditional Firearms and Weapons => General Interest => Topic started by: Two Steps on November 12, 2010, 04:21:40 PM

Title: Gain Twist Rifling
Post by: Two Steps on November 12, 2010, 04:21:40 PM

Can someone explain to me the advantage of Gain Twist Rifling?
I remember reading about it in something that Walter Cline wrote...but I don't remember the advantage (then again, there's a whole lot I don't remember nowadays).
Thanks,
Al

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Post by: Hank in WV on November 12, 2010, 05:48:32 PM

I don't have any personal experience with it but I know a fella that does gain-twist. He explains that you can use very hot loads without stripping the patch. The ball will start spinning slowly and speed up farther down the barrel.

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Post by: Two Steps on November 12, 2010, 07:12:36 PM

Thanks Hank...that sounds familiar...I think    IIFC, Cline was talking about match rifles, and maybe paper patched bullets.?.
Al

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Post by: Gordon H.Kemp on November 12, 2010, 07:25:41 PM

I think the theory is sound , but to me it would be wasted expense and effort with PRBs. If you were shooting conicals thats a horse of a different color . I feel spinning a PRB at high RPM would actually have a tendancy to create a problem .

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Post by: Two Steps on November 12, 2010, 09:00:43 PM

Yeah Gordy...I think that's what Cline was talking about...conicals.
This whole thing came up because I saw a full stock Hawken over on Track of the Wolf with a gain twist barrel...just got me to thinking (I can do that every now & then...but I ddo get a headache) about it.
Thanks,
Al

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Post by: Gordon H.Kemp on November 13, 2010, 12:16:45 AM

Yeah! , every time I try to reason out a passing thought , it generally goes right on by    
 Its been a longtime since I did much with center fire rifles , but the gain twist was used on several of the early wildcat calibers , 218bee 219zipper 25-06 even the now old 270.  I don"t recall if they ever put the gain twist on a production barrel ?  Some claimed it reduced barrel erosion on the hotter cal,

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Post by: Two Steps on November 13, 2010, 05:18:30 AM

Thanks Gordy...I hope I can find the reference I'm thinking of, later today.  I don't want one...don't need one, I don't shoot hot loads or conicals.  You know how it is when you het a thought or partial memory stuck in your head  
Al

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Post by: Gordon H.Kemp on November 13, 2010, 06:19:35 AM

Two Steps , I"m an expert on the part memory skills  .

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Post by: Hank in WV on November 13, 2010, 06:29:43 AM

I wish mine was that good.

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Post by: pathfinder on November 13, 2010, 08:01:32 AM

Wish what was that good?

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Post by: Loyalist Dave on November 14, 2010, 08:14:16 AM

Guys if one is using conicals, then what is the concern for stripped patches?   :)   So a gain twist allows the ball and patch to overcome inertia at the point of ignition, with only a very slight beginning of the twist, and gradually increases the rate of the twist as the ball is already beginning to torque along an axis, and it is much less stress on the patch to add twist to an already twisting ball, than to do it from the starting point.  The ball is given an optimal twist rate by the time it exits the barrel.  This then in theory gives the ball a stable flight over a longer distance..., increasing the accurate range of the ball.  

Some folks think that it was also done in ML rifles for dangerous big game at standard distances, the velocity of the ball being a good deal higher than in a standard barrel, but soft lead at high velocity deforms so fast on impact that on  DBG animals you actually get less penetration..., and a better chance of the DBG turning on the hunter.  Later when alloy bullets in fixed ammunition were developed, gain twist in some "African" loads was also popular.  When jacketed bullets were invented, the idea pretty much stopped for the copper or nickle could take the torque without rupture,....,  until WWII and Korea, where the idea was again used to provide extra punch in a high vel 20mm Anti-tank gun but it wasn't the spin on the round, but the torque on the gun and the mount that was the problem..., and that last saw use in the US Army in the 1960's

LD

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Post by: Captchee on November 14, 2010, 09:42:21 AM

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Guys if one is using conicals, then what is the concern for stripped patches?

  well for one some of the European muzzle loading rifles of the later 19th century used a cloth patched conical . The  Swiss  Stutzer  and German Jeagerguwehree “spelling “
  to name a couple  .

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Post by: Gordon H.Kemp on November 14, 2010, 11:49:54 AM

L.D. very good , very good basic discription of the theroy behind the purpose of the gain twist . However , its my opinion that with reasonable max loadings of the PRB (soft lead) that it takes but a very low rate of spin to stablilize the RB . This , to me , is a theroy best applied to modern CF weapons where HV long conicals with hard alloy coatings need to be spun at high RPM to stablize the projectile at extended ranges as the velosity falls off , or the projectile will tumble and key-hole before it impacts the intended target.  This is one of those theroys that can be discussed for hours  such as the free floating barrel as opposed to a glass bedded barrel .  
        When they first announced the R.E.A.L. bullet , the first thing that came to my mind was someone had stumbled across the successfull use of the pre-engraved rotating bands on the rounds used in the short lived recoiless rifles used with good effect in Korea , and applied it to muzzle loaders . For myself , I"ll stick to the more common slow twist and a patched soft lead round ball.  

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Post by: Uncle Russ on November 14, 2010, 03:22:44 PM

FWIW: I have read that when Sam Colt sold the US Gov't. a phony bill-of-goods regarding the manufacture of the 1861 Colt Rifle, one of his strongest arguments was progressive, or gain twist.

He also claimed his Colt Rifle would be much better manufactured than the current Springfield, yet the current supply level of extra parts for the Springfield would be interchangeable with his new Colt. (You may have to think about that one for a moment.)

He also claimed that the progressive twist barrel was much more accurate than the plain or constant twist because a round ball, or conical, traveling through the bore would meet increased resistance at the point of progressive rifling, thereby creating a longer and more even pressure curve, resulting in greatly improved accuracy.

Samuel Colt was one of this Nation's greatest gun builders.... he was also a pretty good salesman.

Uncle Russ...

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Post by: Two Steps on November 14, 2010, 03:58:12 PM

Well. I Googled Gain Twist Rifling and got more options than I can put here.  A lot of it is about modern rifles (and pistols), but there is info out there about MLs too.  I'll try and grab one of the ML blurbs later and post it here.
Al

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Post by: Gordon H.Kemp on November 14, 2010, 04:40:57 PM

No matter if it's a slow twist , a fast twist or a gain twist , "dem dar grooves spin thet ball , like  da button on a out house door "

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Post by: Sir Michael on November 15, 2010, 02:28:43 PM

Gordon,  :rotf  :rotf  :toast

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Post by: Loyalist Dave on November 17, 2010, 10:57:19 AM

Ah but let us not use what has been learned about ballistics in the past two centuries to cloud what was known back then to those who made gain twist...,

Mr. Kemp is correct, it takes a very little turn to stabilize a round ball.  This was known.

It was "known" that at least a minimum 1/4 turn prior to exiting the muzzle was needed to stabilize a round ball, and that American and German rifles, especially the Germanic target rifles, had faster twists than that minimum, with the Germans often using very fast twist on those rifles.  (Source Instructions for The Formation and Exercise of Volunteer Sharp-Shooters Barber 1804)  Barber also noted that such fast twist rifles had several problems including "disagreeable recoil" and tougher to keep clean, both not wanted in a military rifle, and his observations influenced the Baker Rifle.

Rifle shooters of the time, especially in Germany where target shooting was much more of an advanced competition than in the United States, wanted faster twists as they thought they were  necessary..., today we know this isn't true for the patched round ball, but it was part of the idea behind the gain twist.  Again not faster RPM, but their "percieved" need for a fast twist coupled with higher MV to be accurate at very long ranges.  

I'm not suggesting that the gain twist in a ML barrel has any major advantage, especially now that we have round bottom rifling, I was simply explaining what was the accepted idea behind it.  


LD

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Post by: Gordon H.Kemp on November 17, 2010, 05:31:32 PM

L.D. thanks for that bit of information . I think the most of us tend to forget that the Germans were well advanced in target rifles and competition prior to the early 1800s . Also the fact that many of the early gun makers in the Colcnys  were bilingual .

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Post by: Loyalist Dave on November 17, 2010, 09:33:56 PM

Yes, I was actually "floored" when I saw how specialized they had become with their rifles 200+ years ago, and not just for the gentry, while I had thought that it was mostly a rural, frontier pastime, and an American one at that.  

LD