Core Rifle Systems AR-15 Barrel Nut Steel Matte Black

?Barrel nut is made from steel drawn through a special die and stress relived in a precisely controlled furnace, giving it high resistance to metal fatigue and distortion. Barrel nut won't warp and will stand up to years of hard use. Fits all standard AR-15/M16 upper receivers and barrels. Mfg: Core Rifle Systems SPECS: Steel, phosphate finish, matte black.