Barrel: 20" 416R Stainless steel. Chambered in 5.56 NATO, with a 1:7 twist, M4 barrel extension, and a rifle-length gas system. The barrel is finished off with a PSA 15" Hex Full Picatinny M-Lok Free Float Rail, .750 gas block, and A2 flash hider. Upper: Forged 7075-T6 A3 AR upper is machined to MIL-SPECS and hard coat anodized. These uppers are made for us right here in the USA by a mil-spec manufacturer. Bolt Carrier Group and Charging Handle not included.