Advanced Armament Co. AR-15 Flat-Top Upper Assembly 300 Blackout (7.62x35mm) 1:7" Twist 16" Barrel with KAC URX II Modular Free Float Quad Rail Handguard with Integral Front Sight , Blackout Flash Hider
The Advanced Armament Complete Upper Receiver Assembly in 300 AAC Blackout is a complete, pin-on replacement for your standard AR-15 lower receiver. The 4150 Chrome Moly Vanadium Steel Barrel comes with a 1 in 7" twist, M4 feed ramps, low profile steel gas block and protective Black Nitride finish inside and out for durability and corrosion resistance. The barrel's muzzle is threaded with a 5/8"-24 pitch for easy attachment of a sound suppressor, and is topped off with an effective AAC 51-T Blackout Flash Hider.
The Upper features a forged M4-Style Flat-Top Receiver onto which a Knight's Armament Free Floating URX II Modular Quad Rail Handguard with Integral flip up front sight is attached. The URX II creates a full length top rail when matched with the flat-top upper. A Full Auto Bolt Carrier with internal chrome lining houses the Carpenter 158 Steel Bolt, and is heat treated with a properly staked gas key.
This 300 Blackout Upper employs the versatile Carbine Length Gas System, making it suitable for use with Subsonic or Supersonic loads, either Suppressed or Unsuppressed. However, subsonic ammunition may not always cycle reliably under adverse conditions without a sound suppressor attached.