Author Topic: Gain Twist  (Read 1557 times)

Offline Tim May

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Gain Twist
« on: January 07, 2022, 01:34:44 AM »
Gain Twist rifling is it good for
shooting round ball or conical
bullets ? Any experience pros
or cons ?
Tim

Offline Fyrstyk

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Re: Gain Twist
« Reply #1 on: January 07, 2022, 01:44:20 AM »
I have gain twist in two .58 caliber guns that I only shoot roundball with.  I can't say for sure that it is better than a regular twist, but the accuracy of both barrels is outstanding.

Offline Bob Roller

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Re: Gain Twist
« Reply #2 on: January 07, 2022, 02:26:02 AM »
I know that with round balls and the short bullet called the Pickett "ball" work well with a gain twist.
Rifles made by Harry Pope did their best when used as a muzzle loader and his barrels had a slight
gain and they used a long bullet that was lubricated,usually about 32 caliber.
Bob Roller

Offline Carl Young

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Re: Gain Twist
« Reply #3 on: January 07, 2022, 04:46:56 AM »
Bartlein barrels https://www.bartleinbarrels.com/barrel-faq:
I’ll quote what Pope (Pope was one of the greatest barrel makers from a bygone era. His barrels along with Schalk who he learned from and gives credit to and Schoyen, and Zischang made barrels for the Schutzenfest type of guns/shooting in the late 1800’s to early 1900’s) said around a 100 years ago first. “The advantages of the gain twists are three. 1st The twist being less at the breech, gives less friction to the bullet; it therefore starts easier and quicker, giving the powder less time to burn on in front of the chamber, which therefore fouls less than in a barrel of uniform twist at the same necessary muzzle pitch (twist). 2nd The slight change in angle of the rifling, in connection with choke bore (lapping choke bore of the barrel), effectually shuts off any gas escape of gas and prevents gas cutting, which is another case of imperfect delivery. 3rd It holds a muzzle loaded bullet in position much better than a uniform twist…

Now I (Bartlein) will add some more to this. First off I feel this applies more to a lead bullet shooter ... With a gain twist barrel the bullet cannot go to sleep. The rifling is always putting a fresh bite on the bullet as it goes down the bore of the barrel. This is why I always go back to a cut barrel being better than a button barrel. A cut barrel even with a straight twist is more uniform and consistent than a button barrel. With button rifling the button can hit a hard spot/soft spot in the steel and it will slow the button down. The button could speed back up and do the twist it’s suppose to be doing but either way you end up with a non uniform twist and it the twist keeps getting slower towards the muzzle. These two things are a accuracy killers and lead to consistency problems/fliers etc… I feel even a slight gain twist will help accuracy wise... For the most part I would say there is no velocity gain in a gain twist barrel with the same load. What has been conveyed to us and it goes back to Popes 1st point is that shooters have noticed that they can run a slightly heavier powder charge vs. a shooter with a straight twist barrel. As the bullet is starting easier into the rifling my only guess is the pressure isn’t spiking as fast or is delaying the pressure curve. Hence forth they can get more velocity out of the gain twist barrel. I feel pressure is pressure and that the twist doesn’t have anything to do with pressure for the most part but my only guess is that the gain twist like I said earlier is delaying the pressure curve...


If you want to go further get a copy of The Story of Pope's Barrels by Ray M Smith
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Offline Dphariss

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Re: Gain Twist
« Reply #4 on: January 07, 2022, 05:18:16 AM »
The gain twists seems to have come about with the Picket bullet. It was more twist sensitive than the RB and some pretty aggressive gains were used 1:48 to 1:30 to 1:36. A picket is pretty short and has a very short driving band and will shoot in such a twist.
Harry Pope’s comments on sealing the bore are probably not quite correct unless VERY hard bullets were used OR smokeless powder, remembering that Pope was making barrels well into the 20th c. BP has an amazing ability to make and undersized bullet fit the bore with no gas cutting. Bullets .010” under groove will shoot fine with BP. So long as the design prevents nose slump.
For a bullet barrel, based on what I have been told by a guy who has experience in the making of gain twist barrels, I would not use more than 1/2” gain. Such as starting at 16 and ending at 15 1/2. This stops any possibility of the twist slowing at the muzzle. This BTW could have been the reason the gain came into use in the first place. This could easily have been a problem with a wooden, shop made guide. Something the RB would not care about but would likely be troublesome with a picket.
 I think all the Colt percussion revolvers had a gain.
And Bartlein knows gains and I would defer to him in anything I have posted here.
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Offline JHeath

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Re: Gain Twist
« Reply #5 on: January 07, 2022, 05:25:30 AM »
Bartlein barrels https://www.bartleinbarrels.com/barrel-faq:


 What has been conveyed to us and it goes back to Popes 1st point is that shooters have noticed that they can run a slightly heavier powder charge vs. a shooter with a straight twist barrel. As the bullet is starting easier into the rifling my only guess is the pressure isn’t spiking as fast or is delaying the pressure curve. Hence forth they can get more velocity out of the gain twist barrel. I feel pressure is pressure and that the twist doesn’t have anything to do with pressure for the most part but my only guess is that the gain twist like I said earlier is delaying the pressure curve...


If you want to go further get a copy of The Story of Pope's Barrels by Ray M Smith

Extending the leade on a barrel I have read can allow for more velocity, the gas has volume in which to expand and the bullet has distance to overcome standing inertia before engraving pressure and the standing inertia of non-rotating mass are added. It takes energy to rotate an object so I guess fast twist at ignition is like kicking a bowling ball and gain twist is like giving a bowling ball a gentle push and then kicking it.

Offline Dphariss

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Re: Gain Twist
« Reply #6 on: January 07, 2022, 08:36:16 AM »
Bartlein barrels https://www.bartleinbarrels.com/barrel-faq:


 What has been conveyed to us and it goes back to Popes 1st point is that shooters have noticed that they can run a slightly heavier powder charge vs. a shooter with a straight twist barrel. As the bullet is starting easier into the rifling my only guess is the pressure isn’t spiking as fast or is delaying the pressure curve. Hence forth they can get more velocity out of the gain twist barrel. I feel pressure is pressure and that the twist doesn’t have anything to do with pressure for the most part but my only guess is that the gain twist like I said earlier is delaying the pressure curve...


If you want to go further get a copy of The Story of Pope's Barrels by Ray M Smith

Extending the leade on a barrel I have read can allow for more velocity, the gas has volume in which to expand and the bullet has distance to overcome standing inertia before engraving pressure and the standing inertia of non-rotating mass are added. It takes energy to rotate an object so I guess fast twist at ignition is like kicking a bowling ball and gain twist is like giving a bowling ball a gentle push and then kicking it.

In some cases the velocity can be increased by the increased powder charge or pressures can be lowered with the same charge. But I can’t get into examples without getting too far into brass suppository  guns.  And It has nothing to do with MLs. AND with BP it may result is larger velocity variations and other accuracy issues. But in a breech/muzzleloader this would be different I suspect.
The gain twist with a CLOTH PATCHED bullet, like the Picket, can eliminate stripping the patch since the projectile is not spun up as fast and once its rotating the twist can be increased to what will give the best accuracy. But unless using a large RB close to an ounce or more and trying to spin it too fast I can’t see it being important to the RB.
Nor do I think that there is anyway to start a bullet with a gentle push with BP. The initial acelleration is pretty energetic with this propellant. More so than with grey powder.
Crisis is the rallying cry of the tyrant”. James Madison

Offline Tim May

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Re: Gain Twist
« Reply #7 on: January 07, 2022, 09:55:25 PM »
Thanks for all replies. Just undisighted
What to with this barrel it is marked
J.J.J.J.
Large. No other stampings
Tapered 1and 1/8 to 1 in. 45 cal.
36 in long gain twist.
Thanks
Tim

Offline recurve

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Re: Gain Twist
« Reply #8 on: January 07, 2022, 10:02:13 PM »
.54 at 50 yds group sight in then adjusted front sight
Talk to Bobby Hoyt, he  does gain twist as does Colerain
Gain twist.      Bobby Hoty you have to call

This is from the colerain web site
We offer GAIN/progressive twist rifling as an option in our barrels. All gain twist barrels will shoot round balls very well, plus allow the use of conical and saboted bullets. To arrive at the desired curve for rifling gain twist some precise mathematical figuring is required, in other words you cannot just throw in some curve and hope it works. With gain twist the bullet starts at a much slower twist rate than what it leaves the muzzle at. As the bullet travels down the bore the twist rate starts to increase, first slowly then faster as it goes. For instance, let’s say in a 42” barrel the rifling machine is set to cut a twist of around 1 in 96” at the breech then the muzzle twist rate will be around 1 in 48”. If the twist rate is increased to a faster rate at the muzzle the twist rate at the breech will also increase, but at a lesser rate than the muzzle. This type of rifling in a muzzleloader barrel comes literally as close as possible to give one barrel the ability to handle most forms of bullets and with a high precision of accuracy. If any of you shoot long range centerfire rifles you might have noticed that the big names in high power barrel manufacturing have also started to make GAIN twist barrels.

Our gain twist barrels are being used by hunters and target shooters. Hunters in the western states are hunting large game because of the ability to shoot conical’s and saboted bullets. We offer gain twist in all rifled calibers except 36 cal.

Offline Standing Bear

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Re: Gain Twist
« Reply #9 on: January 08, 2022, 12:55:37 AM »
I agree w DPfarris. All projectiles resist sudden acceleration forward (recoil) and rotation (torque). The heavier the projectile the more resistance. All PRB have only a small tangent engaging the rifling even w a tight combination and deeper rifling like .012”. A larger caliber PRB, say .50 up, when fired with heavy charges can cause the condition called stripping the rifling.  A gain twist starting the rotation at a slower pace and increasing through the barrel will have less tendency to strip the rifling and predict greater accuracy.

The reverse is true IE 1/48 straight twist, .004-005” rifling, .490 ball, .005” patch probably won’t be very accurate with 120 gr FFFg.

Just my $2. Pennies aren’t worth much anymore 
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Offline Daryl

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Re: Gain Twist
« Reply #10 on: January 08, 2022, 01:46:13 AM »
Thanks for all replies. Just undisighted
What to with this barrel it is marked
J.J.J.J.
Large. No other stampings
Tapered 1and 1/8 to 1 in. 45 cal.
36 in long gain twist.
Thanks
Tim

The .58 Large Barrel I had, was choked for sure but did not have a gain twist.
Are you sure it's got a gain twist?
Daryl

"a gun without hammers is like a spaniel without ears" King George V

Offline WadePatton

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Re: Gain Twist
« Reply #11 on: January 08, 2022, 04:19:09 AM »
Here's what I got sorted in my head the last time, or maybe the other last time we discussed "gain twist": That rifling is/was rarely perfectly cut such that there is "zero" gain from one end to the other. That it may vary to gain a little bit here and lose a little bit there, and what we measure is actually an average of those variations.  But that if the muzzle it cut where the gain is negative, reduced accuracy is the usual result.  And thus intentionally using a gaining rate of twist when rifling a barrel should always give a positive gain at the muzzle, avoided the accuracy loss inherent to a negative gain.

I left out some details for "brevity", but I retell this because when I first heard of gain twist, this wasn't how it was explained. Makes a great deal of sense to me now, but I don't know how much more accurate modern machining is than the old ways. Perhaps enough to diminish the chances of a negative gain at the muzzle? If gain is always more accurate why isn't all rifling cut with gain?
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Offline Tim May

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Re: Gain Twist
« Reply #12 on: January 08, 2022, 05:03:50 AM »
Thanks for all replies. Just undisighted
What to with this barrel it is marked
J.J.J.J.
Large. No other stampings
Tapered 1and 1/8 to 1 in. 45 cal.
36 in long gain twist.
Thanks
Tim

The .58 Large Barrel I had, was choked for sure but did not have a gain twist.
Are you sure it's got a gain twist?
Darlyl , pretty sure looking thru breech rifling looks
slow. Looking in the muzzle end is noticeably faster twist.

Offline Daryl

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Re: Gain Twist
« Reply #13 on: January 08, 2022, 05:38:58 AM »
Could be, Tim.
I would expect Bob Roller should Know for sure.
A long time barrel maker here in Northern BC, now retired, said as he pulled the buttons through the barrel, he would
attempt to advance the ROT slightly, at the muzzle.  He didn't claim any better accuracy than the "big" houses in the States,
just that his bls. would give as good accuracy as Shilen's barrels.
I've shot many amazing groups with Bevin King's barrels. It shows something that Dan alluded to, in that the rate of increase
needs only be a little bit.
I do know that modern BR shooters have barrels 'gauged' & "charted", and cut ahead of an increase in the rifling twist, if possible,
from a much longer rifled blank.
I read about this back in 1996, so that technology has been around for a while. It was noted, that this was likely where "Screamer"
barrels came from.
Daryl

"a gun without hammers is like a spaniel without ears" King George V

Offline Dennis Glazener

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Re: Gain Twist
« Reply #14 on: January 08, 2022, 02:49:23 PM »
Please do not continue making posts about revolvers of any type, they are against ALR rules! I have removed several posts this morning. They feed on each other and other members think its ok to do the same.

Read our rules here: https://americanlongrifles.org/forum/index.php?board=541.0
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Offline Hungry Horse

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Re: Gain Twist
« Reply #15 on: January 08, 2022, 08:47:39 PM »
 Late Charles Slotterbeck guns were primarily gain twist. He was not only a gun smith, but a well known Schutzen competitor as well. So if there wasn’t an advantage he wouldn’t have used it.

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Offline hanshi

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Re: Gain Twist
« Reply #16 on: January 08, 2022, 10:58:21 PM »
About all I can add to the subject is my own experience with gain twist.  One of my .45 rifles has a GT barrel and is extremely accurate.  But OTOH I can't honestly say it's more accurate than some of my other barrels in that caliber.  More accurate?  Inconclusive.  Less accurate?  Absolutely not!
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Offline Bob Roller

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Re: Gain Twist
« Reply #17 on: January 08, 2022, 11:23:09 PM »
Thanks for all replies. Just undisighted
What to with this barrel it is marked
J.J.J.J.
Large. No other stampings
Tapered 1and 1/8 to 1 in. 45 cal.
36 in long gain twist.
Thanks
Tim

The .58 Large Barrel I had, was choked for sure but did not have a gain twist.
Are you sure it's got a gain twist?
Darlyl , pretty sure looking thru breech rifling looks
slow. Looking in the muzzle end is noticeably faster twist.
That barrel was probably rifled on the machine Bill Large and I built.It had a pronounced gain and pushing a tight
patch thru made it very noticeable.I shot a 58 made with it as a test on a gun that Bill made for that purpose and
with over 70 grains of 3fg it had a keen "crack" when it fired,almost like a high velocity breech loader.
Very accurate a well.
Bob Roller

Offline smylee grouch

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Re: Gain Twist
« Reply #18 on: January 08, 2022, 11:30:23 PM »
A friend of mine had one of Numrich Arms kit guns in 45 cal that was gain twist. Once you found the right combo it shot very well but was very charge sensitive. Vary your powder charge by any more or less than about 5 grains and groups really opened up.

Offline Daryl

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Re: Gain Twist
« Reply #19 on: January 09, 2022, 02:41:03 AM »
I recall hearing the same thing back in the 70's and/or 80's SmyleeGrouch, converning those gain twist .45's. I thought they were Hopkins and Allen barrels, but likely Numrich as you say.
Daryl

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Offline smylee grouch

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Re: Gain Twist
« Reply #20 on: January 09, 2022, 04:00:32 AM »
Daryl, I think they might have H&A barrels but the kit he built I think was from Numrich Arms. I don't know the connection between H&A and Numrich. IIRC there was a picture in an old Numrich catalog that showed what they said was a Pratt & Wittney rifling machine but I cant remember if it was one company or the other.

Offline Jeff Murray

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Re: Gain Twist
« Reply #21 on: January 09, 2022, 04:55:36 AM »
My 58 caliber Hawken has a Hoyt barrel with gain twist.  It shoots round ball very accurately with a variety of charges.  I did some experimenting with a 610 grain heavy skirted mini which gave OK accuracy but stuck with the round ball load.  Much more pleasant to shoot.

Offline Levy

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Re: Gain Twist
« Reply #22 on: January 09, 2022, 06:07:07 AM »
I purchased a percussion rifle about 8 months ago that was once a nice half stock rifle (.34) and the only markings on it are on the barrel (warranted increase twist).  Is that the same as a gain twist?  James Levy
James Levy

Offline WadePatton

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Re: Gain Twist
« Reply #23 on: January 09, 2022, 06:24:52 PM »
I purchased a percussion rifle about 8 months ago that was once a nice half stock rifle (.34) and the only markings on it are on the barrel (warranted increase twist).  Is that the same as a gain twist?  James Levy

Sounds very much like it.

Measure the twist in very short segments, see what you've got perhaps.  And remember, it doesn't take much. The fellows that impressed me with the "insights" I posted above were convinced that any gain was better than no gain. Say an increase from 48 to 48.25 would be enough to ensure positivity (increasing gain) upon exit-which is all that is needed.

And again, they were satisfied-as I am now that the elimination of the possibility of negative gain at the muzzle was the benefit. Not that it shoots better than any "perfectly even" twist (neutral-neither gaining or losing rate) at the muzzle. But that negative gain is the evil to avoid. 

I'll go dig that conversation/discussion up again sometime. Seemed legit to me at the time, and no one offered evidence to the contrary.


« Last Edit: January 09, 2022, 06:28:18 PM by WadePatton »
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Offline utseabee

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Re: Gain Twist
« Reply #24 on: January 09, 2022, 09:32:23 PM »
I have gain twist barrels from Bobby Hoyt in a .54 and a .62. I have only shot patched round balls. I can't say that is has been any more accurate than the non gain twist barrels, but they do seem to shoot flatter with less powder. Over all, I really like it. It really seems to make the most difference in the .62
The difficult we do at once, the impossible takes a little longer.