Diamondback 223Wm18M50B7R OEM Replacement 223 Wylde 18" Mid-Length Black Nitride 4150 Chrome Moly Vanadium Steel Replace Your Barrel, Or Finish Your Build With This 18" Black Nitride Barrel From Diamondback! Made Of 4150 CMV With a midlength Gas System. Length: 18" Model: OEM Replacement Twist: 1:7" Finish: Nitride Barrel Type: Midlength Medium Profile