This Barrel Kit offer all parts forward of the Upper Receiver with a MIL-STD-1913 Railed Gas Block. The M4 Profile Crowned Barrel is machined from 4150 Chrome Moly Vanadium steel – chrome lined and rifled 1 x 9″ Right Hand twist. The muzzle is finished with a plain crown to comply with legal restrictions in States where threaded muzzles and flash hiders are prohibited. The bayonet lug has been machined off the MIL-STD-1913 Railed Gas Block. The Kit includes Barrel, Barrel Extension with M4 Feed Ramps, Barrel Nut, Front Hand- guard Cap, MIL-STD-1913 Railed Gas Block with Sling Swivel, M4 Double Heat Shield Hand- guards, Delta Ring, Weld Spring, Snap Ring, and Gas Tube & Pin – all top quality parts made in the USA.