Manufactured 100% in-house from gun-barrel-quality bar-stock, the Faxon 450 Bushmaster 16 Gunner Big Bore barrel starts with 4150 Chrome Moly Vanadium Mil-Spec steel. From there, the barrel goes through a battery of tests at each operation until finished in Nitride and final inspected. This beautiful 450 Bushmaster 16 Gunner Big Bore barrel is individually checked for headspace by precision custom hardened gauges.Just what is the Gunner profile?The Gunner profile is a blend of the best performing profiles of all time, Government and Pencil. The gunner profile mimics the well-known government taper, and from the gas block forward, Faxon's innovation takes over and the Gunner moves to their famed pencil front end.Removing weight from the front of the barrel ensures maximum versatility and keeps material to the rear to maximize heat resistance and mitigate whipProduct Specifications Manufacturer: Faxon Firearms Part #: 15A45016C16NGQ UPC: 816341024250 Barrel Material: 4150 CMV Barrel Type: Button Rifled Caliber: 450 Bushmaster Twist: 1:16 Length: 16" Profile: Gunner Big Bore Gas System: Carbine Inside Finish: QPQ Nitride Outside Finish: QPQ Nitride Muzzle Thread: 11/16-24 TPI (Threads Per Inch) Gas Block Diameter: .875 Journal Length: 1.1" Barrel Extension: Big Bore Barrel Extension Weight: 1.72 lbs Magnetic Particle Inspected! 11-degree Target Crown