FightLite MCR 5.56x45mm NATO Threaded Rifle Barrel Mid Length 16.25in 1-7 1/2x28 Manganese Phosphate Black. 56x45mm NATO Black Mag Phosphate - Complete barrel assembly for use with MCR rifles and upper receiver assemblies. Includes barrel extension with fixed headspace gas block assembly 4 position regulator piston flash hider and dovetail cover. Specifications for FightLite MCR 5.56x45mm NATO Threaded Rifle Barrel: Manufacturer: FightLite Finish: Mag Phosphate Additional Features: 1-7in. Twist FightLite BBL002 5.56x45mm NATO Black Mag Phosphate FightLite BBL002: MCR 5.56x45mm NATO Threaded Rifle Barrel Mid Length 16.25in 1-7 1/2x28 Manganese Phosphate Black