Cloak Industries OEM MFR56 5.56x45mm NATO Threaded Rifle Barrel 13 inch 1-7 Twist Nitrided. 56 barrel. Whether you plan to shoot out your first barrel or want to enable continuous and effective sustained fire this is what youll need. Many 5.56 barrels are designed to maintain accuracy through 10000-15000 rounds however the heat produced by rapid/sustained fire can lead to premature wear if proper cooling time is not allowed. Why run the risk? Grab a spare barrel for your MFR56. Specifications for Cloak Industries OEM MFR56 5.56x45mm NATO Threaded Rifle Barrel: Manufacturer: Cloak Industries Caliber: 5.56x45mm NATO Barrel Profile: Nitrided Barrel Twist Rate: 1-7 Barrel Material: Steel Features of Cloak Industries OEM MFR56 5.56x45mm NATO Threaded Rifle Barrel Complete with adjustable gas block and carry handle Package Contents: Cloak Industries OEM MFR56 5.56x45mm NATO Threaded Rifle Barrel Cloak Industries CLK-13-RB: OEM MFR56 5.56x45mm NATO Threaded Rifle Barrel 13 inch 1-7 Twist Nitrided