Re: WTB - AR15 with 1x7 twist barrel
Posted: Wed Dec 26, 2012 5:44 pm
Well, if you want to get REALLY nitpicky about it, it really doesn't matter what bullet weight/barrel twist you use if you don't have a H&K. if you don't have an H&K, you suck.4t5 wrote:If you want to get real nit-picky, it is NOT about the overall length, but the "bearing" length, that is, the length of the bullet that actually engages the rifling. So since the bearing lengths are different, a .308 220 FMJ will not stabilize out of a 10 twist barrel, while a .308 220 30-30 (round nose) bullet will. Essentially everyone who shoots .223 competitively uses Sierra Matchking 69, 77 and 80 grain bullets.Heartland Patriot wrote:Well, since the can of worms has been opened, its actually about the LENGTH of the projectile, not its weight specifically. It just so happens that as you make a bullet longer, it tends to be heavier. The tighter the twist, the longer a bullet that can be stabilized (and thus, generally, the heavier a bullet, too). There is an actual formula for it, but I'm not a ballistics guy or a math wiz. You can do a search online and find it pretty easy, though.
I suck.
X3.
