Bear Creek Arsenal BC-15 300 BLK 8.5" 30rd M-LOK Pistol

300 Blackout was drawn up for exactly this gun. The cartridge burns nearly all its powder in the first eight or nine inches of barrel, so an 8.5" BC-15 gives up almost nothing to a longer one, while a 5.56 of the same length is throwing energy out the muzzle as flash. The chrome moly barrel is parkerized and fed by a pistol length gas system, which is the correct port position for a barrel this short.

Supersonic 110 to 125 grain loads behave like a short 30 caliber carbine round inside two hundred yards. Drop to heavy subsonic ammunition and the same gun runs quiet behind a can, which is the reason a lot of people buy into the cartridge in the first place. Magazines, bolt carriers, and lowers are shared with 5.56 AR-15s, so the only part that changes is the barrel. The M-LOK handguard free floats and gives you room for a light, the buffer tube is adjustable with no brace fitted, and one 30rd magazine comes along. Keep 300 BLK and 5.56 magazines clearly marked and stored apart.