Barrel: Barrel is made for Palmetto State Armory by FN Manufacturing using their proprietary blend of Hammer forged chrome molly vanadium that is referred to as "Machine Gun Steel" by virtue of its use in FN's M249 and M240 weapons. The hammer forging process work hardens the steel, making it more durable. In addition, the chrome process for the bore allows for a lining almost twice as thick as a standard M16 for enhanced durability. Chambered in 5.56 NATO, with a 1:7 twist, M4 barrel extension with extended feed ramps, and a Mid-Length gas system. The barrel has an M4 profile, is Mil-spec phosphate coated, and MP/HP tested. The upper is finished off with a Geissele .750" diameter Super Gas Block that is pinned to the barrel, A Geissele Super Modular MK14 M-Lok 13.5" Rail, and a Pin/Weld SilencerrCo ASR. Upper: Forged 7075-T6 A3 AR upper is made to MIL-SPECS and hard coat anodized black for durability. These uppers are T-Marked engraved. Bolt Carrier Group: Father's of Freedom BCG by Microbest with Sprinco Extractor Spring and Carpenter 158 MP Bolt. Lower: Complete Sabre-15 lower with black Moe SL-S stock and grip. Black finish. Marked multi-caliber. Comes Standard with Springco Buffer Spring, Battle Arms Development Pivot/Takedown Pins, Sabre 2-Stage DLC Trigger, JP Reduced Power Springs, and Anti-Walk Pins.