This Bear Creek Arsenal AR-15 5.56 NATO Complete Pistol has a 10.5" M4 barrel with a parkerized finish, and features a 1:7 twist, with a carbine length gas system. This 5.56 AR-15 pistol includes a 9.5" MLOK rail, a forged upper receiver, a BCA AR15 Bolt Carrier Group, Flash Hider, rear charging handle, and mil-spec forged AR-15 multicaliber lower with brace.