Diamondback DB15 Obsidian 5.56mm NATO 16in OD Green Cerakote Semi Automatic Modern Sporting Rifle - 30+1 Rounds - This Diamondback DB15 Rifle features a medium 4150 chrome moly barrel, mid-length gas system and a shot-peened Mil-Spec 8620 bolt carrier. It utilizes 7075-T6 aluminum receivers, 15" M-Lok handguard, Magpul MOE-K2 grip, and a Magpul CTR stock. Threaded Barrel: 1/2 x 28 Obsidian Muzzle Brake Magpul MOE K2+ Grip