Gain twist rifleing?

[far_shot]

Gain twist is when the rifling starts out slow and the rate of twist is essentially a gradual increase in the rate of twist from the breech to the muzzle.
Since spin is a factor in flight stabilization, would that be a benefit to diabalo shape pellets or slugs?
Can projectiles be spun too fast?
Would it make spin drift worse?

 

[biohazardman]

Since spin is a factor in flight stabilization, would that be a benefit to diabalo shape pellets or slugs?

Although I can see your point many of the barrels on our airguns shot MOA or less already so no reason to go to the extra trouble or expense.

Can projectiles be spun too fast?

Sure you can spin them too fast.

Would it make spin drift worse?

Depends on the projectile and the barrel and the speed you shoot it.

 

[mtnGhost]

I thought about getting some custom slug barrels made with gain twist rifling. I don't think they would benefit pellets as much (at least the pellets that I shoot). 

 

[Mrshosted]

I think the only thing you stand to gain is a dirty barrel and a pellet of odd shape in flite. As the pellet ran down the barrel with the twist changing it would work like helix of a end mill shearing off lead. 

 

[towle]

Gain twist is when the rifling starts out slow and the rate of twist is essentially a gradual increase in the rate of twist from the breech to the muzzle.

That would produce a lot of drag, the pellet would have to swag to the changing twist rate moving down the barrel

 

[Guest]

It works with pellets that stabilize even without spin and twist applied progressively towards muzzle is so gentel. But if we take 224cal for example and have progressive twist at end of 1:10for example you mostlikely wont engage that spind at end anymore with soft lead and just shave through it. I struggle to see reason for this seeing velocity gain would be minimal or well none existing and with all the trouble it might cause. 

 

[billygee]

Feel BIO pretty much hit the nail on the head

(But FWIW)

Then again barrel material could be a factor, if you want to get technical :

http://www.quackenbushairguns.com/Airgun_barrels.htm

Here we even have Micro Groove

What is Micro Groove rifling?

Micro-groove rifling creates a bore with many more lands and groves than conventional rifling, this results in a bullet or bullet jacket that is not deeply grooved or distorted as conventionally made barrels. The less distortion, the greater the accuracy.