Diamondback DB1721K061: Diamondback Firearms DB15 rifle uses a gas-impingement system and high quality CNC machined components. Features a 4140 chrome moly barrel, A3 Flattop upper receiver, carbine length gas system, 12\" M-LOK rail, MOE grip, A2 Flash hider muzzle and a Magpul MOE Carbine stock This model includes two upper receivers, one chambered for .223/5.56 NATO and an extra upper chambered for .300 Blackout. Select between two of the most popular defensive rifle calibers with a simple receiver swap. It\'s like owning two rifles for the price of one! Proudly made in the USA.