Barrel: 8" chrome moly steel barrel. Chambered in 9mm, (9×19), with a 1/10 twist. The barrel is nitride treated for durability and finished off with a Palmetto State Armory 7" Lightweight M-Lok free-float rail and a bird cage style A2 flash hider. Upper: Forged 7075 T6 aluminum AR-V slick side upper is hard coat anodized black for durability. These upper receivers are made for us right here in the USA.Bolt Carrier Group: AR-V 9mm BCG. Nitride treated 8620 steel bolt, with an enhanced firing pin and external 5.56 style extractor. The bolt carrier group is compatible with most aftermarket fire control groups. Lower:. Forged 7075 T6 aluminum and then hard coat anodized, these lowers are purpose built to accept AR-V U9 and CZ Scorpion Magazines. The lower is assembled with a Palmetto State Armory MOE EPT SBA3 lower build kit with a Magpul Grip and SB Tactical SBA3 Pistol Stabilizing Brace. This product features last round bolt hold open.