Gain Twist

[BPOR11]

I am planning on putting together an AR-10. It will be geared more for accuracy, so I plan on a heavier (prolly fluted) 20 or 22 inch barrel.

Looking for opinions and experience on gain twist rifling. I see claims of benefits and it seems to make sense to me.

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[jeff68]

I know nothing but if the bullet engages a 1:8 twist and MV of 3000 fps thats 270k rpm. Seems a ramp up would be beneficial.

 

[arrowshooter]

Had know idea what gain twist was so I found this:

I'll have to agree with jeff68 about the potential benefits of the bullet twist being able to "ramp up".

 

[JuglansRegia]

Who makes a gain twist rifled barrel these days?

 

[turq]

Bartlein? In a AR-10?

 

[Otter]

Gain twist was a big thing in bench rest shooting a few years ago. Seems to be a fad that has since passed. Based on competitive results I don't think it helped or hurt accuracy. Most the guys have since gone back to uniform twist barrels. You can read about it on the Accurate Shooting website.

 

[TTSX]

Out of sheer curiosity, does anyone have an idea what a "loss twist" barrel might do? Or if one ever existed?

 

[Andy54Hawken]

I have a rifle from the late 1840's -early 1850's with gain twist rifling...I also have seen it on rifles with a much earlier date.
At one time I owned a Austrian rifle from 1690 with " straight " rifling ( No twist )

I did shoot a early American long Rifle with "loss twist" rifling...it seemed accurate enough...
As in I could make hits with a unzeroed to me rifle at 100 yards or so...
But I haven't seen many rifles with a "loss twist"...so I can't say just what advantage there was , if any......

Early rifle makers , just like today's rifle makers , liked / like to see just what happens if I try this...
Andy

 

[Stomper]

@AndyinEverson I do the same thing with peanut butter.

 

[Andy54Hawken]

@AndyinEverson I do the same thing with peanut butter.

Crunchy or smooth....Err...Nevermind...
Andy

 

[Red98422]

Weren't the old Carcano rifles gain twist? I vaguely remember folks having accuracy issues if they cut down the barrels because of it (old magazine article maybe?)

 

[BPOR11]

Gain twist was a big thing in bench rest shooting a few years ago. Seems to be a fad that has since passed. Based on competitive results I don't think it helped or hurt accuracy. Most the guys have since gone back to uniform twist barrels. You can read about it on the Accurate Shooting website.

I couldn't find any manufacturer that offered any significant product. IIRC, there was one, but the gain was so minor that there might as well have not been my at all. Most is for ordinance work.

 

[tac]

Out of sheer curiosity, does anyone have an idea what a "loss twist" barrel might do? Or if one ever existed?

Trying to mechanically induce a LOSS of rotation whilst the bullet is ACCELERATING up the bore poses some interesting mechanics... Me, I'm laying money on it never having happened.

 

[turq]

Once again: Bartlein makes gain twist and their web site will give you expert opinion on the benefits.
They do not offer a drop in fit, too many differences in manuf. specs.
Top maker of barrels. But for an AR-10 barrel you would need it finished by your gunsmith.

 

[OldBroad44]

SW .460 XVR revolver has a gain twist barrel, for greater accuracy, they say.

 

[tac]

Hey, all, don't get 'gain twist' muxed ip with 'progressive rifling'. The first means that the spiral get somewhat tighter as it goes up the barrel to the muzzle, and second means that it starts off deep-cut at the chamber end, and gets progressively less deep as it approaches the muzzle.

An example of the latter can be found in the Enfield model 1861 carbine - AKA Musketoon - which starts off deep-cut at the chamber to ensure positive engagement of the skirted Minié bullet and is much less by time it gets to the muzzle.

 

[osprey]

Out of sheer curiosity, does anyone have an idea what a "loss twist" barrel might do? Or if one ever existed?

I bought a brand new Remlin lever in 45-70 with a sort of loss twist. It was missing a complete land from the factory.

 

[Steel Head]

It definitely has advantages especially with solids but I wouldn't bother with it in a AR10 personaly.

Bartlein makes some excellent gain twist barrels.

 

[turq]

At Bartleinbarrels.com testimonials

Tom Helak from Gillette,Wy
Wy. State Service Rifle Championship (& past three consecutive years)
600 yard prone slow fire
Bartlein gain twist (1:13" X 1:6.5")
90 gr Berger Match Boat Tail

I knew I had seen something recently on gain twist bbls
I wonder if the "transition" happens after the gas port?

 

[BPOR11]

But I haven't seen many rifles with a "loss twist"...so I can't say just what advantage there was , if any......

I'm thinkin they were just installed backwards on a Monday after a bender