Diamondback Firearms OEM Replacement Barrel FN Herstal M16 5.56x45mm NATO 16in Heavy Profile Carbine Length 1-8 Twist Non-Threaded 4150 CrMov Black. 56x45mm NATO 16" Carb - Replace your barrel or finish your build with this 16" black nitride barrel from Diamondback Made of 4150 CMV with a carbine-length gas system. Specifications for Diamondback Firearms OEM Replacement FN Herstal M16 Non-Threaded Barrel: Manufacturer: Diamondback Firearms Color: Black Finish: Nitride Fabric/Material: 4150 CrMoV Caliber: 5.56mm Barrel Length: 16 in Barrel Profile: Heavy Gas System Length: Carbine Length Gas Block Journal Size-Diameter: .750 in Threads per Inch: Non Threaded Barrel Twist Rate: 1-8 Flutes: No Gun Make: AR Platform Gun Model: M4 Gun Type: Rifle Length: 16 in Diamondback 556C16H50B8NYR OEM Replacement (No Threads) 5.56x45mm NATO 16" Carb What firearm models does the manufacturer say Diamondback Firearms OEM Replacement FN Herstal M16 Non-Threaded Barrel is compatible with? The manufacturer suggests that Diamondback Firearms OEM Replacement FN Herstal M16 Non-Threaded Barrel is compatible with M4Diamondback Firearms 556C16H50B8NYR: OEM Replacement Barrel FN Herstal M16 5.56x45mm NATO 16in Heavy Profile Carbine-Length 1-8 Twist Non-Threaded 4150 CrMov Black Nitride