Barrel: 20" Chrome moly vanadium steel, chambered in 5.56 NATO, with a 1:7 twist, M4 barrel extension, and a rifle-length gas system. The barrel is nitride finished for accuracy and durability. Barrel is finished off with a .750" diameter F-marked Front Sight Base, PSA Classic Handguards, and an A2 flash hider. Upper: Forged 7075-T6 A3 AR upper is made to MIL-SPECS and hard coat anodized black for durability. May or may not have T-marks and features a mil-spec finish. These uppers are made for us right here in the USA by a mil-spec manufacturer. Bolt: Bolt is made of Mil-spec shot-peened Carpenter 158 steel. The gas key is secured with grade 8 fasteners and staked per mil-spec. The Bolt carrier is an 8620 steel M-16 profile carrier.