Barrel: Phosphate coated 4150V Chrome Moly steel. Chambered in 5.56 NATO, with a 1:8 twist, M4 barrel extension, and a carbine-length gas system. Barrel is is finished off with a standard handguard, F-Marked gas sight base, and A2 flash hider. Upper: Forged 7075-T6 A3 AR upper is machined to MIL-SPECS and hard coat anodized, features a forged upper receiver. These uppers are made for us right here in the USA by a mil-spec manufacturer.*These uppers will have cosmetic blemishes that do not affect function. This may include, but is not limited to, machining marks under the finish, scratches, or variations in the finish color.*