Rosco Manufacturing Purebred, Barrel, 300 Blackout, 16, Pistol Length Gas System, Fits AR-15, Bead Blasted Finish, Silver PB-16-HB-300BLK-8-P This Rosco 16" 300 Blackout (300 BLK) Barrel is perfectly suited for precision carbine shooters that plan on running only supersonic ammo" or are building a well-balanced hunting platform.