Barrel: 4" chrome moly vanadium steel barrel. Chambered in 9mm (9x19), with a 1/10 twist rate. The barrel is nitride treated for durability and finished off with a PSA 5" Lightweight Hex Full Picatinny M-Lok Free Float Rail, and a PSA Fluted Flash Can muzzle device. Upper: Newly designed 6061 Billet T6 Aluminum slick side upper is hard coat anodized black for durability. Featuring T-marks, these upper receivers are made for us right here in the USA. Bolt Carrier Group: Gen 4 Hybrid 9mm BCG. Phosphate Coated 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. Flash Can: Palmetto State Armory's new fluted flash can. This is a solid 6061 aluminum device that is designed to direct muzzle gases and the muzzle flash forward. Threaded 1/2-28 and black military-style hard anodizing. THIS DEVICE IS NOT DESIGNED TO REDUCE RECOIL, MUZZLE RISE, OR FLASH SIGNATURE. This device is designed to direct gasses and noise forward away from the shooter and enhance the weapon's appearance. *PSA Can't Guarantee Function With EndoMag 9mm Magazines