Diamondback Barrels 7.62x39mm AR-15 Carbine Barrel 16in 1-9.5 Twist Rate 5/8 X 24 TPI 7.62X39C16M50B9.5. 62x39mm AR-15 Carbine Barrel is machined in house on state-of-the-art CNC machines and are thoroughly inspected at multiple stages of the build...