mongoosesnipe Wrote:I would go with 14.5 with preminatly attached flash hider or a 16 to save on paperworkThis.
Unless you have a specific reason otherwise, there isn't much good to be had from a barrel that short (12.5") in .308 caliber.
I run a 10.5" Grendel, but I'm burning a lot less powder than a .308.
Now if you wanted to just do it for the fun of it--- that's different.LOL Some people love massive muzzle blast and flash. That's the whole reason for an HK51. They have "ooh" factor when playing at the range, but they aren't really practical at all.
I really nice compromise would be a 12.5" Grendel like some of the other guys have built. My 10.5" is fine for normal woods hunting, but the extra 2" would certainly help ballistics while still remaining pretty compact in the AR15 envelope. The AR10 platform is just too chunky though for being handy. I may still buy a Colt LE901 when they release them, but it's only because I'm a pony fan. It'll mostly just be a waste of money. A .308 carbine isn't really going to kill critters any deader than my 10.5" Grendel already does.... Plus it'll weigh more and be less wieldy.
One more thing--- If you plan on running a can (you'll get real tired of the noise and concussion eventually!), a .308 SBR will be brutal on the baffles of your suppressor. You'll have much more unburnt powder sandblasting your blast baffle, and your can's lifespan will decrease considerably ($$$-$$$$). The Grendel is much milder by comparison.