"The Proof Research AR-Type 16"" Carbon Fiber Barrel Blank delivers enhanced functionality in AR platforms along with lightweight precision that outperforms standard AR barrels. Proof Research AR barrels feature the Caliber Matched Gas System (CAMGAS) tuned specifically for the cartridge and length of the barrel. By moving the port location, Proof Research ensures that the pressure is the same as what the AR-10 platform was originally designed around delivering softer recoil impulse, less fouling, better extraction, and less wear and tear on brass. The Barrel Blank features a steel core wrapped with high-strength, aerospace-grade carbon fiber impregnated with a proprietary matrix resin, creating a barrel that's up to 64% lighter than traditional steel barrels of similar size and contour. Barrels are guaranteed for headspacing to the specifications of the JP Enterprise Enhanced Bolt. Intermediate-length gas system; gas tube is included. 16"" long, 1:10"" twist. Steel core wrapped in aerospace-grade carbon fiber Extreme accuracy and temperature resistance Up to 64% lighter than traditional steel barrels of the same size/profile Caliber Matched Gas System Guaranteed for headspacing to the specs of the JP Enterprise Enhanced Bolt 16"" long, 1:10"" twist, 5/8""-24 threaded muzzle Intermediate-length gas system (tube included)"