I didn't know who else to ask.

[densa44]

The question is "progressive rifling"? In artillery pieces the rifling starts slow and as the projectile accelerates in the barrel gets tighter and tighter. In other words makes the shell spin faster.

The physics is pretty simple, higher RPMs keep the bullet on course. iN A SHOT OF 20 miles this would matter a lot.

My question is, to the long range BR guys, has this been tried in shoulder mounted rifles? If yes, do you know what the results?

[elkhunter11]

Gain twist rifling has been around for many years, but it has never been that popular.

[Dick284]

We have RKS in Wemborne who’s been doing gain twist barrels for decades.

I have 2 of their barrels, one in 25’06, the other is my .280AI.

Both shoot really well.

Is it the be all end all, I highly doubt it, but the theory behind it is pretty cool.

The Italians had gain twist barrels on their Carcano’s I do believe.

[catnthehat]

I have owned about 8 gain twist barrels by Ron Smith, he builds an excellentbbarrrl.
Hugh Williamson's short range BR barrels I believe are gain or " progressive " twists though not nearly as extreme rate progression as Ron's.
The great Harry Pope was a proponent of the Gain twist as well.
Cat

[ScottFitter]

What's the theory on a gain twist? If 8t starts at a 10, but finishes at a 7.5, the projectile is still spinning at that 7.5 rate, it just toom longer to get it there.
Maybe it's my simple mind, but the only thing I can think of is that it's "maybe" still accelerating the spin as it leaves the barrel, but that wouldn't last for long after it exits the barrel.

[Dick284]

Originally Posted by ScottFitter

What's the theory on a gain twist? If 8t starts at a 10, but finishes at a 7.5, the projectile is still spinning at that 7.5 rate, it just toom longer to get it there.
Maybe it's my simple mind, but the only thing I can think of is that it's "maybe" still accelerating the spin as it leaves the barrel, but that wouldn't last for long after it exits the barrel.

Less rotational energy wasted getting the bullet rotating, so lower pressures, is the theory. Like having a transmission in the barrel. That’s the theory……

Take a bullet at 3000fps, and put it thru a 1 in 22” twist barrel and you’ll have a bullet rpm near 98000 rpm
Take the same bullet at the same speed and put it into a 1 in 11.5” twist barrel and you’ll have a bullet rpm near 187000 rpm.

My 25/06 is a gain twist barrel of 1 in 22 up to 1 in 11.5……..

[Ronji]

Originally Posted by Dick284

Less rotational energy wasted getting the bullet rotating, so lower pressures, is the theory. Like having a transmission in the barrel. That’s the theory……

Take a bullet at 3000fps, and put it thru a 1 in 22” twist barrel and you’ll have a bullet rpm near 98000 rpm
Take the same bullet at the same speed and put it into a 1 in 11.5” twist barrel and you’ll have a bullet rpm near 187000 rpm.

My 25/06 is a gain twist barrel of 1 in 22 up to 1 in 11.5……..

That's really interesting when you explain it.

I was always wondering the difference. We were discussing how that would work over a few beverages a while back.

Thanks!

[ScottFitter]

Originally Posted by Dick284

Less rotational energy wasted getting the bullet rotating, so lower pressures, is the theory. Like having a transmission in the barrel. That’s the theory……

Take a bullet at 3000fps, and put it thru a 1 in 22” twist barrel and you’ll have a bullet rpm near 98000 rpm
Take the same bullet at the same speed and put it into a 1 in 11.5” twist barrel and you’ll have a bullet rpm near 187000 rpm.

My 25/06 is a gain twist barrel of 1 in 22 up to 1 in 11.5……..

Thank you for the explanation.