Barrel: 4150V Chrome Moly Vanadium steel Nitride barrel is chambered in 5.56 NATO, with a 1:7 twist, M4 barrel extension, and a mid-length gas system. The barrel is finished off with a pinned F-marked front sight post in the Rifle position with a sling swivel, rifle-length 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. Featuring machined T marks, and a mil-spec finish. These uppers are made for us right here in the USA by a mil-spec manufacturer.