American Tactical AR-15 Complete Upper Features The American Tactical AR-15 Complete Upper is chambered for 5.56 and .223 Rem built around a 16 barrel with a 1-in-8 twist rate that stabilizes a wide range of bullet weights for versatile shooting. The barrel is finished in black nitride for corrosion resistance and comes threaded 1/2x28 to accept a flash hider compensator or suppressor. A phosphate coated bolt carrier group and a micro low profile gas block come fully assembled so the upper is ready to run as soon as it is mated to a lower receiver. A 7075-T6 aluminum upper receiver houses the assembly for a strong lightweight foundation. A 15 free-float M-LOK handguard surrounds the barrel giving builders room to mount lights grips or bipods without disturbing barrel harmonics. Poly flip-up front and rear sights ship installed providing a usable backup sighting system right out of the box. This upper is compatible with any mil-spec lower receiver or parts making it a straightforward option for a new build or an upgrade to an existing rifle. The American Tactical AR-15 Complete Upper for sale at GrabAGun gives builders a finished ready-to-mount upper assembly without the need to source and fit individual parts. American Tactical AR-15 Complete Upper Specifications Manufacturer: American Tactical Model: AR-15 Complete Upper Type: Upper Receiver Caliber: 5.56 / .223 Rem Barrel Length: 16 Twist Rate: 1-in-8 Barrel Finish: Black Nitride Thread Pattern: 1/2x28 Color: Black Sights: Poly Flip-Up Adjustable Handguard: 15 M-LOK Free-Float Upper Material: 7075-T6 Aluminum Available At: GrabAGun