Question about twist rates and supersonic bullets.

[Grendel65]

Bullet geometry, such as length and shape not just weight is also a factor to consider when matching a bullet with barrel twist. A 110 solid copper bullet has more mass (longer) than a jacketed bullet of the same weight and may result in tighter groups in a fast twist barrel over a slower twist.
The only way to know for sure how your rate of twist will group a particular bullet is to go shoot a variety of bullets.

[2bad4u2]

I'm glad this topic has come up because I've got a 1:11" twist Broughton barrel sitting in the corner with no particular use for. I was thinking of cutting it to 20" and use it for supersonic only 300 Blackout. I'm not sure how much extra velocity I'd get over the 16" I'm using now. If it's an insignificant amount, I wouldn't bother spending the money to re-barrel another rifle. Though, if I go this route, I likely won't use bullets any heavier than 168gr.

168 Hornady A-MAX's are fairly accurate in my 16" Shilen 1:8" and I can't see things getting much better than what I'm doing now. My initial interest in bullet testing has been in the intermediate weights of 150gr.-170gr.

I haven't had any experience with the heavy bullets but my initial outtings with light weight bullets have been disappointing. The 110gr. FMJ .30 Carbine bullets were a complete bust and the 125gr. Nosler BT's weren't extremely accurate in the limited load testing I've done so far.

I've seen some posts regarding the use of .311" 123gr. FMJ projectiles for plinking. I happen to have (500) of those on hand so I might experiment with these some. Hopefully, excessive pressures and copper fouling won't be an issue. I'm thinking Lil' Gun might be a good powder to start with as it seems to have a similar burn rate to H110 but produces lower pressures.

[Warrior1029]

I am shooting a S&W upper, twist is 1:8. I am getting .750" 5 shot groups @ 100yards with 125 grain Nosler Ballistic Tips using 17.7grains of H110, COAL is 2.075".

[300Blk]

S&W twist is 1/7.5.

[JonProphet]

I'm pretty new to the 300 BLK scene and this is my excuse to use my stripped lower. So my question is, I only want to shoot supersonic. Is there a specific twist rate I should be looking for? I want to go to an 18" barrel rather than a 16". I would like to find the barrel in stainless steel. I'm looking to build a short to medium range bench shooter.

Later,

-JD-

[din]

I'm pretty new to the 300 BLK scene and this is my excuse to use my stripped lower. So my question is, I only want to shoot supersonic. Is there a specific twist rate I should be looking for? I want to go to an 18" barrel rather than a 16". I would like to find the barrel in stainless steel. I'm looking to build a short to medium range bench shooter.

Later,

-JD-

you should be good with one of the 1:8 18" bbls wilson's been selling.