Gain twist barrels?

Mattm8725

Staff Sargeant
Feb 13, 2017
36
1
8
New Mexico
#1
Has anyone tested this option, and if so was there any noticable difference between gain or normal barrel twist? I guess to me it just makes sense in my mind but I've been wrong plenty of times before.
 

Mattm8725

Staff Sargeant
Feb 13, 2017
36
1
8
New Mexico
#4
Nat -Just if there was a big noticable difference really?

Badfinger - thanks I don't know how I've never seen that before!

Thanks guys I just watched the video I guess my only other question is why this isn't done more?
 

tna9001

Sergeant of the Hide
Aug 4, 2017
205
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Asheville NC
#6
Litz tested the effects of different twist rates on velocity here. In his test, velocity correlated with the barrel twist at 1.33fps per inch of twist (between 1:12-1:8). I would assume the correlation would change depending on the bullet and caliber but it seems a difference of .5" twist is going to result in a very small difference in velocity. Litz's test does show a gain twist barrel increases velocity though, the 1:8 was at 2649fps and the 1:10-1:8.3 was 2656.

Frank, in a standard length barrel, let's say 24", would you say that the bullet is fully engraved to the rifling, that there is no slipping of the bullet at the end of the bullets travel in the barrel?
 
Jun 26, 2012
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N. Carolina
#7
Litz tested the effects of different twist rates on velocity here. In his test, velocity correlated with the barrel twist at 1.33fps per inch of twist (between 1:12-1:8). I would assume the correlation would change depending on the bullet and caliber but it seems a difference of .5" twist is going to result in a very small difference in velocity. Litz's test does show a gain twist barrel increases velocity though, the 1:8 was at 2649fps and the 1:10-1:8.3 was 2656.

Frank, in a standard length barrel, let's say 24", would you say that the bullet is fully engraved to the rifling, that there is no slipping of the bullet at the end of the bullets travel in the barrel?
Twist and velocity have very little if anything to do with each other. Twist is about stability, length is about velocity
 

Lowlight

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#9
I have a bunch of gain twist barrels, everything from small gains, 8.5 to 7.7 up to 13 to 5 in another. Currently, I have gain twists for 260, 6CM, and 338, the results are outstanding.

Gain twist done right work, Bartlien is gain twist done right. They forwarded the barrels to Hornady who tested pressure and I spoke to them about it. They (Hornady) found no negative effects and no pressure issues. There is no slipping or laying the rifling on the bullet, it is not adding extra grooves in the barrel or anything like that. It's much worst to over twist a barrel, it harms the bullet more so than using a gain twist. A gain twist solves the problem of pressure, speed, etc, by spinning the bullet at a more gradual rate vs jamming it hard right off the bat.

Gain Twist barrels work.
 
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Feb 20, 2017
277
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#10
I have a bunch of gain twist barrels, everything from small gains, 8.5 to 7.7 up to 13 to 5 in another. Currently, I have gain twists for 260, 6CM, and 338, the results are outstanding.

Gain twist done right work, Bartlien is gain twist done right. They forwarded the barrels to Hornady who tested pressure and I spoke to them about it. They (Hornady) found no negative effects and no pressure issues. There is no slipping or laying the rifling on the bullet, it is not adding extra grooves in the barrel or anything like that. It's much worst to over twist a barrel, it harms the bullet more so than using a gain twist. A gain twist solves the problem of pressure, speed, etc, by spinning the bullet at a more gradual rate vs jamming it hard right off the bat.

Gain Twist barrels work.

How does one identify how much gain is needed? And how does one also determine how slow or how fast to start/end? For example, if you determine the optimal twist rate for whatever bullets you want to use in X caliber is a 10 twist, does one do a difference of one? Start at 10.5 and end at 9.5? Etc.
This is very interesting info.
 

tna9001

Sergeant of the Hide
Aug 4, 2017
205
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Asheville NC
#11
From Bartlein:

"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. So you don’t see problems as early like hard bolt lift etc"
 
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Lowlight

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#13
I started off very conservative, except for that 13-5 which was built for a specific bullet and was spec'd out by the designer. Otherwise, I think people can a bit more aggressive than I went.

For a 6.5 caliber, I would do an 8 to 7 twist,

For a 30 cal, I would do a 10 to 8,

Same for 338

The 6mm can go about 8.25 to 7.5

There are service rifle guys using aggressive twists, like 14 - 6 or something, they claim to use these twists because they can mix heavy and light bullets in the same competition at the same time. So for the short range stuff they go light and work up to 90gr heavies.

There is a school of thought that says you can over twist a barrel, or in their mind, you can't over twist one. But we see and have very good evidence you can, and the limiting factor is the jacket technology, and lead vs solid. A solid bullet can be over twisted, a jacketed bullet not nearly as much as they claim. You risk one of three outcomes, you damage the jacket and leak lead out like a pinwheel, or the entire bullet will come apart in the air. The other issue is, you shift the lead under the jacket and the bullet is out of balance. That gives people that odd flier, as it can be enough to throw the bullet off, or it can affect the BC, lowering it. It's like having excessive runout in the bullet/load.
 

Fursniper

Captain, USMM (retired)
Feb 13, 2017
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#14
Frank did that video quite a while back. Seemed like for awhile he (& others) were hot on the trail of LH gain twist advancement foe awhile. For the last year or so, perhaps longer, the subject seems to have vanished from these boards & I am wondering why. Has the technology of gain twist fallen out of favor? No one seems to discuss it any longer. The preponderance (if not all) of inventory I see from barrel makers appears to be RH twist. ELR doesn't seem to be favoring GT as far as I can see. For awhile it was a hot topic, seemed to make perfect sense & then discussions vanished. Are people moving toward GT or has it be shown to be not any more effective than a regular consistant rate of twist? Can anyone elaborate? As I'm still considering GT on a new barrel I'd sure like to be more knowledgeable on the topic.
 

Lowlight

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#15
I am the only one talking about it, the others are all happy to repeat the tired old thing.

Gain twists work, Bartlein sold a bunch, and a guy posted on FB about Warner Tools 6.5s using a LH Gain Twist he ordered.

I just haven't ordered any barrels in a while
 
Feb 20, 2017
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#18
What about barrel life expectancy? With out the slipping/skidding it seems to me you would get better barrel life? Frank would this stand to reason or am I off track?
You could also burn more powder with a gain twist before you start running into pressure issues so I'd think the difference might be very marginal for those who do run hot loads on GT barrels. Just some more food for thought.
 

bjay

Private
Oct 19, 2009
2,535
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Aloha state HI
#20
My 6.5x47 gain twist 8-7 left twist..is the most accurate rifle i got..really stable SD shot this card sideways at 100yards two bullets left over..either the first try split or tje second onei was aiming on indicator..its laser!!! I would definitely do it again


Screenshot_2017-12-18-09-35-34.png
 

Fursniper

Captain, USMM (retired)
Feb 13, 2017
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#21
The potential velocity advantage of GT it seems to me is minimal compared to the biggest advantage of GT which, IMO would be for use in ELR as a faster twist should translate to a more stable bullet for a longer period of flight time thus extending the distance & time before transonic velocities start destabilizing the bullet, especially the very long nosed solids. It just makes sense that achieving a faster spin rate than would ordinairly be possible without seriously deforming the bullet and/or destroying the jacket would be very advantageous shooting at extreme distances. Yet I don't think the current major players in that game seem to be pursuing GT technology. There seems to be alot going on in bullet & case design but not much or anything on barrels (other than they continue to get longer). I just don't understand the apparent reluctance to develop this & take advantage of the obvious benefits considering all the other advances people are working on & striving for in the world of extreme distance.
 
Feb 20, 2013
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#22
The potential velocity advantage of GT it seems to me is minimal compared to the biggest advantage of GT which, IMO would be for use in ELR as a faster twist should translate to a more stable bullet for a longer period of flight time thus extending the distance & time before transonic velocities start destabilizing the bullet, especially the very long nosed solids. It just makes sense that achieving a faster spin rate than would ordinairly be possible without seriously deforming the bullet and/or destroying the jacket would be very advantageous shooting at extreme distances. Yet I don't think the current major players in that game seem to be pursuing GT technology. There seems to be alot going on in bullet & case design but not much or anything on barrels (other than they continue to get longer). I just don't understand the apparent reluctance to develop this & take advantage of the obvious benefits considering all the other advances people are working on & striving for in the world of extreme distance.
The problem is, as usual, there is no enough hard data to draw any valid and technical conclusion most especially when it comes to transonic and beyond. I don't buy the argument of a bullet going thru any better with a GT barrel.
 

Lowlight

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#23
Gain Twist is the answer to move barrel technology to the next level.

Unfortunately, the little bit I talk about is not enough to push the manufacturers further. Groups are testing barrels by overtwisting stuff and looking at the transonic results, but very few if anyone is playing with GT stuff. I promote it here and there when I grab a new one. But otherwise, it's just me doing the talking here.

There is a lot of talk about fast twist rates easing the transition to transonic, but like I said, you become subject to the bullet maker on a lot of levels. None of them good. They are not QC'ing every bullet so it doesn't take much to have a defect a fast twist barrel will exploit. Because the bullet has to be shot, they don't follow up. But we know it is happening, and we have seen whole lot bullet recalls in the past. I know some companies are talking about jacket tech, thickening up the jackets because people want to over twist. But you can over twist using a GT barrel and not have the negative.

The bullet is not skidding or laying over multiple grooves, it does not work that way. It's progressive or gradual and not some big change in width, or anything.

It works, it's more forgiving, it's better for a variety of bullet weighs, the advantages are numerous.

Going back to Pope and his rifles, part of the problem is mass production. He was very slow and hand rifled his barrels. He was using LH GT Barrels back at the turn of the 20th Century. He was a Silohoutte shooter, so positional was important and he was absolutely convinced a Right Handed Shooter should be using a LH GT Barrel. His score spoke for themselves, I think it took like 50 years to beat his scores. Once companies went to mass-produced machines to make this stuff, it all went right-handed with standard twist rates but the machines were not capable of doing it until now. So the Tech Died until Bartlein with their Computer Controlled Rifling.

For ELR it is smarter unfortunately not enough guys are hip to this
 
Sep 28, 2012
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#24
Frank, not having special-ordered a barrel before, I'm not familiar with the best way of going about it. I guess an order directly through Bartlein would be best? I've read enough about these that I'm ready to try it on my next barrel, but given lead times for specialty barrels, I need to do it sooner rather than later.
 
Oct 4, 2005
139
1
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Hutchinson, Kansas
#30
I have used the Bartlein Gain twist 1-13 to 1-6.5, in a .223 service rifle, gunsmithed by Joe Carlos for the last two years, they shoot very well. I use it for NRA service rifle competition and in 2016 & 2017 I won the Civilian Service Rifle Championship at the NRA Nationals. I have had good luck with the 90 grain Sierras.
 
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