Douglas 18" barrel is constructed of 416 Stainless with black Cerakote finish. The barrel comes with M4 feed ramps a 1/7 twist and top quality MOA accuracy. The end of the barrel comes with 1/2-28 thread for brakes or flash hiders. Dimpled for a gas block with set screws on 0.500" center-center. Barrel does not come with BOLT. MK12 Mod 1 barrel.