Barrel: The Nitride treated 4150V chrome moly steel is chambered in .300 Blackout, with a 1:5 twist rate, M4 barrel extension, and Pistol-length gas system. This barrel is finished off with a PSA 7.25" Sabre QD Rail, Rifle Speed adjustable gas block, and a Sabre compensator. Upper: Forged 7075-T6 A3 AR upper is made to MIL-SPECS and hard coat anodized 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: Palmetto State Armory complete Sabre-15 lower with SBA5 Brace and Sabre pistol grip. Marked multi-caliber. Comes Standard with Sabre Buffer Tube, Springco White Carbine Buffer Spring, Carbine Buffer. Battle Arms Development Pivot/Takedown Pins, Sabre 2-Stage DLC Trigger, and JP Reduced Power Springs.