Advanced Armament AR-15 Pistol 300 AAC Blackout 9" Upper Receiver Assembly KAC URX III
This Advanced Armament Corp. AR-15 Pistol Upper Receiver Assembly in 300 AAC Blackout is a pin-on, ready-to-shoot top end for use with any standard AR-15 lower receiver. The Mil-Spec 4150 Chrome Moly Vanadium Steel Barrel comes equipped with a 1 in 7" twist, M4 feed ramps, low profile steel gas block, and is finished inside and out with a protective Black Nitride treatment for superior durability and corrosion resistance. The muzzle is threaded with a 5/8"-24 pitch for easy installation of a silencer, 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 III Modular Rail System is rigidly attached. The URX III creates a full length top rail surface when matched with the flat-top upper to accommodate almost any desired sighting arrangement, and allows shooters to add modular rail sections along its length only where needed for adding accessories while keeping the remainder of the handguard slim, smooth, and snag-free. A heat-treated, full auto bolt carrier with internal chrome lining and properly-staked gas key houses a Carpenter 158 steel bolt assembly.
This 9" 300 Blackout Upper utilizes a Pistol Length Gas System and is compatible with most Subsonic or Supersonic ammunition, with or without a sound suppressor in place. However, some subsonic ammunition may not always cycle reliably under adverse conditions or in a severely fouled firearm without a sound suppressor attached to provide extra backpressure.
IMPORTANT NOTES (From the Manufacturer):