Hughes Ballistics 5.56 CMV Barrel 16in HBAR Fluted Mid-Length 1-7 Twist 1/2x28 Thread Black Nitride HBHBAR16556F. 56 chambered 16-inch HBAR Mid-Length Barrel is machined from 4150 Chrome Moly Vanadium steel with a Black Nitride Corrosion Resistant...