Lead & Steel 5.56mm Threaded Barrel 16in Government Mid Length 1-8 Twist Black. 56 16? barrel dimpled is fully stress-relieved & 11 target crowned with a gas nitride finish. Our barrels are ported conservatively. Paired with a heavy buffer you may experience stoppages with underpowered steel-cased ammo. To guarantee reliability with all ammo types use a standard carbine buffer + spring & run the system with a magazine of full power M193/M855 if new before shooting steel. After an initial 30rd break in steel-cased ammo can be used without issue. Specifications for Lead & Steel 5.56mm Threaded Barrel: Manufacturer: Lead & Steel Color: Black Finish: Nitride Fabric/Material: 4150 Chrome-Moly Vanadium Steel Caliber: 5.56mm Gas Block Journal Size-Diameter: .750 in Threads per Inch: 1/2x28 Barrel Material: 4150 CMV Steel Flutes: No Gun Make: AR Platform Weight: 1.15 lb Features of Lead & Steel L&S Match Grade 4150 Nitride Barrel - 5.56Mm Nitride Mid Length Match Grade Package Contents: Lead & Steel L&S Match Grade 4150 Nitride Barrel - 5.56Mm Nitride Mid Length Lead & Steel 121223: 5.56mm Threaded Barrel 16in Government Mid Length 1-8 Twist Black