What do you all think about the "Gain" or progressive rifling twist in a barrel"

[drpatton]

I talked to a gun maker today and he is a true believer in the gain twist. His PRBs barrels start with a 1:70 at the breech and end up with a 1:48 at the muzzle. He uses a 42" barrel to accomplish this.

 

[WP79Vet]

No experience... but seems like it might be a good way to keep soft lead or patched bullets from jumping shallow rifling.

 

[Bad Karma]

I talked to a gun maker today and he is a true believer in the gain twist. His PRBs barrels start with a 1:70 at the breech and end up with a 1:48 at the muzzle. He uses a 42" barrel to accomplish this.

Bobby Hoyt will do gain twist in a shorter barrel than 42” . He claims the main advantage is not better accuracy but increased velocity over standard twist rates. As much as 300 fps. He’s very good at this. Maybe the best in the country currently. I tend to take him at his word.

 

[drpatton]

Bobby Hoyt will do gain twist in a shorter barrel than 42”

The guy I talked to is Bill Slusser. He and Hoyt are very close friends. It was Hoyt who introduced this twist to him. Slusser doesn't make his own barrels. He has Hoyt or Colerain make them for the guns he makes.

Bill said the same thing. These twists are not more accurate, but attain a higher velocity while maintaining accuracy.

 

[45-70]

I talked to a gun maker today and he is a true believer in the gain twist. His PRBs barrels start with a 1:70 at the breech and end up with a 1:48 at the muzzle. He uses a 42" barrel to accomplish this.

they work good if the right twist., especially with a bullet, as used in long range BPCR or Muzzle loading

 

[Fyrstyk]

My observations with a gain twist barrel that Bobby Hoyt did for me (.54 cal 1:70-1:48 in a 42" barrel) seems to concur with Mr. Hoyt about velocity. The original rifling in the barrel was 1:48 and I was getting 1400FPS at 15" from the muzzle (choreographed) using 70 grains of 3f and a 5.30 ball in a .015 mink oil lubed patch. With the gain twist rifling, using the same load I now get around 1675FPS and accuracy hasn't suffered. I am going to cut down on the powder charge now due to the increased velocity. Gain twist may be a good way to conserve powder without losing velocity.

 

[smokepolehall]

Reading n learning here.

 

[pacanis]

It worked for Lee Harvey.
Apparently.

 

[WP79Vet]

My observations with a gain twist barrel that Bobby Hoyt did for me (.54 cal 1:70-1:48 in a 42" barrel) seems to concur with Mr. Hoyt about velocity. The original rifling in the barrel was 1:48 and I was getting 1400FPS at 15" from the muzzle (choreographed) using 70 grains of 3f and a 5.30 ball in a .015 mink oil lubed patch. With the gain twist rifling, using the same load I now get around 1675FPS and accuracy hasn't suffered. I am going to cut down on the powder charge now due to the increased velocity. Gain twist may be a good way to conserve powder without losing velocity.

If you can cut down on the powder without losing velocity, you'll reduce recoil, too.

 

[drpatton]

It worked for Lee Harvey.
Apparently.

The Carcano has a gain twist?

 

[Bad Karma]

The guy I talked to is Bill Slusser. He and Hoyt are very close friends. It was Hoyt who introduced this twist to him. Slusser doesn't make his own barrels. He has Hoyt or Colerain make them for the guns he makes.

Bill said the same thing. These twists are not more accurate, but attain a higher velocity while maintaining accuracy.

I only have one gain twist weapon, a Pietta Shooters model Remington replica. I need to chronograph the pistol and see what the machine tells me…

 

[pacanis]

The Carcano has a gain twist?

It did.
And if you've ever seen the oddball bullet it shoots... skinny and loooong...

 

[drpatton]

It did.
And if you've ever seen the oddball bullet it shoots... skinny and loooong...

6.5 x 52. I had to look it up. If I remember my History correctly, Oswald bought it through mail order.

A gain twist on a copper jacketed bullet doesn't make sense. The twist was designed to keep lead from stripping the rifling at higher velocities on faster twists. Copper doesn't seem to have that problem.

 

[45-70]

6.5 x 52. I had to look it up. If I remember my History correctly, Oswald bought it through mail order.

A gain twist on a copper jacketed bullet doesn't make sense. The twist was designed to keep lead from stripping the rifling at higher velocities on faster twists. Copper doesn't seem to have that problem.

it also reduces torque on the rifle

 

[pacanis]

6.5 x 52. I had to look it up. If I remember my History correctly, Oswald bought it through mail order.

A gain twist on a copper jacketed bullet doesn't make sense. The twist was designed to keep lead from stripping the rifling at higher velocities on faster twists. Copper doesn't seem to have that problem.

The surplus bullets I had for mine were all lead. I must have gotten rid of it when I sold the rifles.
You had to have the special enbloc clip to shoot the rifle. It's the only way it could be loaded. Other than single shot anyway.

ETA, or maybe they had a sliver coating on them. I found a lousy pic next to a rifle and can't quite make them out.
I know it wasn't copper though.

 

[BP Addict]

According to Ned Robert's book "The Caplock Muzzleloading Rifle," they had gain-twist barrels for competitive long-range shooting back in the late 1800s. They were using paper-patched elongated bullets.

Walt

 

[WP79Vet]

It worked for Lee Harvey.
Apparently.

Thanks for posting that the Carcano had a progressive twist. I knew that the Italian service bullets were about 160 grains, which makes for a very long 6.5 mm bullet, but didn't know that the Carcano had a progressive twist.

Given the mass and the length of such a bullet and the very high rate of twist needed to stabilize it, it makes sense to use a progressive twist so that the bullet starts moving easily, which keeps chamber pressure from rising too quickly, and thus slows down the rate at which the powder burns and enables higher velocities without exceeding pressure limits.

 

[WP79Vet]

I talked to a gun maker today and he is a true believer in the gain twist. His PRBs barrels start with a 1:70 at the breech and end up with a 1:48 at the muzzle. He uses a 42" barrel to accomplish this.

Just don't be doin' nunna that Gain of Twist research now.... We don't wanna give the dang Gummint no excuses fer shuttin' us down!

 

[sheriffjohn]

My limited first-hand knowledge of gain twist was with a friend many years ago. He had good luck with his gain twist barrel and patched round balls.

 

[drpatton]

Just don't be doin' nunna that Gain of Twist research now.... We don't wanna give the dang Gummint no excuses fer shuttin' us down!

I'm not messing with the gain twist. It doesn't improve accuracy. I want to understand it. How can it cause the bullet to accelerate?