Barrel: 13.7" 4150V Nitride. Chambered in 5.56 NATO, with a 1:7 twist, M4 barrel extension, and a mid-length gas system. Barrel is finished off with our Patent Pending 13" Sabre Lock Up Handguard, and a JMAC GFHC-E pin and weld muzzle device. 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: Palmetto State Armory complete Sabre-15 lower with black B5 Sop-Mod stock and B5 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. Made in America and compatible with all AR-15 uppers.