Faxon Firearms 16" Gunner Big Bore .450 Bushmaster barrel. Manufactured 100% in-house from certified 4150 Chrome Moly Vanadium (CMV) steel, fully stress relieved, air-gauge tested, salt-bath nitride finished inside and out, and finished with a polished 11 target crown. The Gunner Big Bore profile blends durability and maneuverability to move balance rearward for reduced shooter fatigue ideal for heavy-caliber AR builds and hunting applications. Each barrel is button-rifled, magnetic particle inspected, and individually headspace-checked with precision hardened gauges. Product Specifications Manufacturer: Faxon Firearms Caliber: .450 Bushmaster Barrel Length: 16" Barrel Material: 4150 Chrome Moly Vanadium (CMV) Barrel Type: Button Rifled Barrel Profile: Gunner Big Bore Barrel Twist: 1:16 Gas System Length: Carbine Gas Block Diameter (journal): 0.875" Gas Block Journal Length: 1.1" Muzzle Thread: 11/16" 24 TPI Barrel Extension: Big Bore barrel extension Inside Finish: Salt Bath Nitride Outside Finish: Salt Bath Nitride (black) Weight: 1.72 lbs Inspection: Magnetic Particle Inspected; individually headspace-checked Muzzle: Polished 11 target crown Compatibility: AR-15 platform (Big Bore builds) Features Manufactured cradle-to-grave in-house for strict quality control Fully stress relieved and air-gauge tested for consistent accuracy Button rifled and salt-bath nitride finished for durability and corrosion resistance Gunner Big Bore profile for improved balance and reduced shooter fatigue Individually headspace-checked with precision hardened gauges Package Contents Faxon Firearms 16" Gunner Big Bore .450 Bushmaster Barrel Warning WARNING: California's Proposition 65 this product can expose you to chemicals known to the State of California to cause cancer or reproductive harm. Check local regulations before purchase.