Upgrade your rifle with this dependable 16 5.56 NATO complete upper receiver. Built for accuracy and smooth performance it features a free-float 15 M-Lok handguard for solid accessory mounting and improved barrel stability. The nitride BCG delivers reliable cycling and low-maintenance durability while the full-length Picatinny rail gives you plenty of room for optics. Ready to pin onto any Mil-Spec lower this upper is built in the U.S.A. and ready for work. – Includes: 16 5.56 NATO barrel (1:8 twist) 15 M-Lok free-float handguard nitride BCG charging handle clamp-on system with steel barrel nut and screws. – Reliable modular and ready to run. – Caliber: 5.56mm NATO – Barrel Length: 16 in. – Barrel Profile: SOCOM – Muzzle Thread: 1/2X28 – Twist Rate: 1:8 – Gas System: Mid-Length – Muzzle Device: A2 – Handguard Length: 15 in.