Caliber 5.56 NATO Barrel Length 16 Barrel Material 4150 Chrome Moly Vanadium Barrel Finish QPQ Corrosion Resistant Gas System Length Mid-Length Gas Block Journal .750" Gas Port Size 0.0785 Barrel Rifling Button Rifling Twist Rate 1:7 inches Thread Pitch 1/2-28 Threaded Barrel Extension M4 Weight (oz) 32oz