Bartlein gain twist barrel

[Hirschi1]

What are your thoughts concerning the "Bartein T Style rifling" aka "Gain twist".
Pros?
Cons?
Good for fast calibers only?
Good for slow Calibers?
Increase of barrel life?
best only for accuracy?
Is It the Future?

I read a little about it in the "Shooting Times" magazine. written by Joseph Von Benedikt.

 

[FearNoWind]

Good for fast calibers only?
Good for slow Calibers?
Increase of barrel life?
best only for accuracy?
Is It the Future?

Interesting topic for which, IMO, the jury is still out.
IMO, they appear to have some promise for smaller caliber lighter weight bullets.
I'm not sure what you mean by "slow calibers". I have some large caliber rifles that move a pill down the barrel at the same velocities as the smaller calibers.
Because, IMO, barrel life is more a factor of throat erosion than wear on rifling, the gain twist barrel would have little or no effect on barrel life.
Most of the critiques I've read suggest that, with .223 caliber 75 - 90 grain bullets, there is some degree of increased accuracy using gain twist barrels. Some of the claims speak to .223 accuracy at 1K. Just because a bullet travels over 1100 FPS at 1K doesn't mean it'll remain stable enough to support consistent accuracy. I haven't seen any comparative on target examples that convince me to accept the claim of gain twist = greater accuracy.
Is it the future? Probably, at least for the short term. We'll have to see if they do in deed prove to be more accurate. But it'll only take one champion rifleman winning an important match using a gain twist barrel to heat up the market.

 

[J E Custom]

There has been lots of post on gain twist and a search will find them.

Hear is just one of those post that might help.

http://www.longrangehunting.com/for...ssive-gain-twist-barrels-aid-accuracy-146459/

J E CUSTOM

 

[Canadian Bushman]

I personally dont see any benifit. Im also curious as to the effect of the changing bullet engraving with have on external and terminal ballistics.

Im not against the idea, but im not going out of my way to give it a try.

 

[Deleted member 46119]

I personally dont see any benifit. Im also curious as to the effect of the changing bullet engraving with have on external and terminal ballistics.

Im not against the idea, but im not going out of my way to give it a try.

I wondered at that one as well. Could not work it out without resorting to math I didn't feel like doing. I don't want to reinvent the wheel if someone else has already figured it out.

If I understand correctly: the benefit is to reduce barrel/rifle torquing but I'd like to get more information on that.

My 8twist 260 torques significantly. I have a 9tw 30 cal that will go into service in a 308/26-Nosler (not the same as the 30-Nosler) so I can sling 200 grain coppers. Too late to do anything about the 9tw but knowing is forewarning.

 

[Canadian Bushman]

I wondered at that one as well. Could not work it out without resorting to math I didn't feel like doing. I don't want to reinvent the wheel if someone else has already figured it out.

If I understand correctly: the benefit is to reduce barrel/rifle torquing but I'd like to get more information on that.

My 8twist 260 torques significantly. I have a 9tw 30 cal that will go into service in a 308/26-Nosler (not the same as the 30-Nosler) so I can sling 200 grain coppers. Too late to do anything about the 9tw but knowing is forewarning.

If the exit speed and final twist are the same whats the reduction in torque?

 

[CB11WYO]

If the exit speed and final twist are the same whats the reduction in torque?

The speed with which it gets to said twist perhaps?

 

[Canadian Bushman]

The speed with which it gets to said twist perhaps?

Outside of my mathematical understanding.
Id sure apreciate an example if anyone can do that equation?

 

[CB11WYO]

Outside of my mathematical understanding.
Id sure apreciate an example if anyone can do that equation?

Me too... Anyone else?

 

[J E Custom]

I personally dont see any benifit. Im also curious as to the effect of the changing bullet engraving with have on external and terminal ballistics.

Im not against the idea, but im not going out of my way to give it a try.

I did some research on gain twist rifling to find out the reason for it in the first place.

As I understand it, The problem with standard rifling is that with High speed projectiles is there tendency to shear the engraving in the bullets because of inertia at firing. old worn out barrels are notorious about this because the lands are worn down and have rounded edges that allow the bullet to jump the rifling to some degree.

When the rifling is very fast it has the same tendency and will slip the bullet jacket if it starts to fast.
the bonded bullets and the mono material bullets have solved the jacket slipping problem and minimized the need for gain twist rifling in many peoples minds.

The Germans started messing with it to hopefully solve the accuracy problems on there really big
guns that had to start a 4000 pound+ projectile rotating. They finally determined the solution was to cut many lands and grooves to give the engraving as much surface area as possible to solved the problem.

The new technology in large heavy projectiles is to use fins to rotate the projectile and use a smooth bore.

It is one of those things that make a lot of sense, but from a practical stand point has not been proven to be better. As someone said ; when someone wins a big bench rest match with a gain twist barrel then it may prove to be better.

Until then I remain open to the idea that it is better.

J E CUSTOM

 

[Edd]

According to Bartlein, the only advantage of a gain twist is to keep the bullet in contact with the lands. You only want a slight gain. An example of slight would be a twist that increases .025" per inch. With a .025" per inch gain, a 10 inch twist would increase to a 9.4 inch twist in 24 inches.

 

[Canadian Bushman]

I did some research on gain twist rifling to find out the reason for it in the first place.

As I understand it, The problem with standard rifling is that with High speed projectiles is there tendency to shear the engraving in the bullets because of inertia at firing. old worn out barrels are notorious about this because the lands are worn down and have rounded edges that allow the bullet to jump the rifling to some degree.

When the rifling is very fast it has the same tendency and will slip the bullet jacket if it starts to fast.
the bonded bullets and the mono material bullets have solved the jacket slipping problem and minimized the need for gain twist rifling in many peoples minds.....

J E CUSTOM

This makes sense to me. I did not consider this until you stated it. I supposed when configured properly it could buy you some more useable barrel life for fast cartridges.

 

[lynxpilot]

Firstly, I claim no expertise, but putting my engineering hat on and looking at the bottom line, it's counter-intuitive to me. I'm assuming the rate of twist increases as the bullet progresses and that's where I have a problem. Point being that toward the end of the barrel, as the threads of the screw start getting tighter the velocity is nearing it's maximum. That to me says that it would be more likely to have more dig into the jacket. Additionally, the angle of the rifling is changing as the bullet moves down the barrel so the gouge from the rifling will be sloppier.

As stated before, jury's still out.

 

[Hirschi1]

Now I don't have a certificate for anything, but waste water collection. However, I do have a good idea at times.
How does this sound? As the bullet travels down a gain twist barrel, picking up speed. either the front of the shoulder (of the bullet) will widen or the rear of the bullet will widen due to the rifling change. There will be a weak area correct? Then, how much of of gap is left in the difference just as the bullet meets the muzzle of the barrel? Probably not much.

In the July issue of "Shooting Times" The author Joseph Von Benedikt of "The O1ne" article quoted Frank Green and I quote " Green pointed out, several major-league benchrest competitors are using Bartlein's gain-twist barrels. Gene Buky won six trophies and set at least three new benchrest records last September with his gain-twist Bartein barrels."

I guess it can't be all that bad.

I am building a custom long range mountain hunting rifle. I want to push the bullet to the limit and squezze out all the accuracy I can. This barrel came into a conversation and I want to hear if others have this barrel and also to see what interest this barrel has.

I haven't decided on a barrel yet, so lets keep the topic rolling please.
Thank you all for you posts.
Shoot Straight
Steve