Adams Arms Upper Mid Base 16 5.56

Upper Receiver: A4 Flat-Top Forged - Barrel Length: 16 - Barrel Contour: Government - Barrel Material: 4150 Chrome Moly Vanadium Steel - Muzzle Thread Pattern: 1/2-28 - Chrome Lined: No - Barrel Finish: QPQ Melonite / Black Nitride - Twist Rate: 1 in 7 - Chamber: 5.56x45mm NATO - M4 Feed Ramps: Yes - Bolt Carrier: 1-Piece w/Integral Piston Strike Face - Muzzle Device: A2 Flash Hider - Gas System Length: Mid Short Stroke Piston Operated - Gas Block Diameter: 0.750 - Handguard: 2-Piece Polymer Mid-Length - Sights: None Single Rail Gas Block - Weight: 4.387 lbs. The 5.56 Midlength Base 16 Upper is a standard mil-spec upper that incorporates the patented Adams Arms technology and the m4 style handguards. The midlength piston system will give you the benefits of a longer forearm by giving the user a longer more ergonomic grip a longer sight radius between the front and the rear sight for quicker sight acquisition and less felt recoil. The piston system parts and the barrel have been treated with our salt nitride Meloniting process making them harder and more corrosive resistant than hard chrome. Add the patented Adams Arms piston system and you'll have an upper that will run cleaner cooler and longer than any other AR upper you own.