300 blackout

[HOG GUNNER]

Originally Posted by rsilvers

There is probably far more variation in 308 dies from brand X to brand Y than there is between 300 AAC BLACKOUT and the 300-221 drawing I saw.

With Chamber pressure at 21,100 psi ? I feel if you make a 300 AAC M1 carb round cheaper than the 30 carb ammo on the market now. You could open a hole new market for this round, and run it in the platform it was made for 30 years ago. With a ream and a little bolt work any M1 carbine could fire this round loaded to an (OAL) of 1.680 with 110gr RNFMJ or 110gr RNSP. and be legal to hunt with. I like hunting with my hand me down carbine from pop in .300 fireball. I would much rather have had it on any of my deployments than any M4. Even at close range 5.56 had all it could do to punch threw block or mud huts. My fireball will make dust out of block at 100 yards with FMJ.

[Shadow 300]

I have been looking for a 300 BLK and was thinking I would use a 8" or 10.5" barrel. I have a YHM 7.62 Phantom for it. The problem is YHM states that they won't warranty their suppressors against baffle strike if a barrel less than 12.5" is used. They claim that regardless of the 1:8 twist that a barrel must be at least 12.5" long to stabilize a subsonic bullet. I have read many posts about people using 8" barrels with the various versions of a 300 whisper. Are baffle strikes a concern with barrels less than 12.5". I had thought bullet stabalization was a function of barrel twist and bullet length, not barrel length. Can someone give me their opinion please?

[rsilvers]

Stability is a function of RPM.

Bullet RPM = MV X 720/Twist Rate (in inches).

So the faster the bullet goes, the better.

Run the Miller stability calculation and see if the value is high enough. 1.5 or more under nominal conditions should be fine.

[Shadow 300]

rsilvers
Is this (mass x velocity) x 720/twist or (mass x velocity x 720) / twist, what are the units? Thanks

[Retooferab]

I think mv = muzzle velocity

[rsilvers]

MV = velocity in fps

[grey2112]

Originally Posted by Shadow 300

I have been looking for a 300 BLK and was thinking I would use a 8" or 10.5" barrel. I have a YHM 7.62 Phantom for it. The problem is YHM states that they won't warranty their suppressors against baffle strike if a barrel less than 12.5" is used. They claim that regardless of the 1:8 twist that a barrel must be at least 12.5" long to stabilize a subsonic bullet. I have read many posts about people using 8" barrels with the various versions of a 300 whisper. Are baffle strikes a concern with barrels less than 12.5". I had thought bullet stabalization was a function of barrel twist and bullet length, not barrel length. Can someone give me their opinion please?

I have an 8" barrelled 9mm with a 9mm suppressor, and have used the same suppressor on my 8" barrelled .300-221 - nary a problem - maybe I'm just lucky, but both the 9mm and the .300-221 out of those barrels are damn accurate and don't keyhole.

[mak91]

I've got a 7inch 300 whisper that I run a aac 7.62 can on, no issues yet with baffle strikes.

[Shadow 300]

Thanks Guys,
The Miller stability calculation can be found at JBM Ballistics. It indicates there will be no problem. It doesn't consider barrel length at all just length of bullet, diameter, weight, muzzle velocity, twist rate, temp, and ambient pressure. I have read before that barrel length is not a consideration so I am comfortable with the result.

[rsilvers]