Bilson Arms Pump Style Forward Charging Upper Assembly 450BMFC-UA 16 inch 1-24 Twist Cerakote Graphite Black A5UFCGB1001. 5 in Barrel Profile: Standard Gas System Length: Carbine Length Threads per Inch: 1/2x28 Handguard Type: Free-Float Muzzle Device: A2 Flash Hider Finish: Nitride Condition: New Gas Block Journal Size-Diameter: .750 in Handguard Length: 15 in Gun Rail: Picatinny Gun Make: AR Platform Barrel Material: 4140 Chrome Moly Vanadium Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Weight: 5 lb Magazine Included: No Mount Type: M-LOK Features of Bilson Arms 556fc-ua 18 inch Pump Style Forward Charging Upper Assembly Manuf in-house More efficient & ergonomic charging patent pending pump style forward charging action billet aluminum Cerakote finish Package Contents: Bilson Arms 556fc-ua 18 inch Pump Style Forward Charging Upper Assembly Steel Nitride Bcg Bilson Arms A5UFCGB1001: Pump Style Forward Charging Upper Assembly BA-15FC 16 inch 1-24 Twist Cerakote Graphite Black