Upper Receiver from an Armalite. Great quality upper. Very low round count. Also comes with Magpul rear sight and hand guard!

Caliber: .223/5.56 X 45 mm NATO
Barrel: 16" Double Lapped, Chrome Lined\Chrome Moly Vanadium MIL-B-11595-E, with M203 Step Down Barrel, Threaded 1/2x28
Rifling Twist: RH 1:9" 52-69 Grain Ammo
Muzzle Device: Flash Suppressor
Front Sight Base: A2
Upper Receiver: Forged, Flattop with Picatinny Rail & Laser Engraved Rail Numbering, 7075-T6 Aluminum