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.

• Chamber: 300 AAC Blackout (7.62x35mm)
• Upper Receiver: Flat-Top
• Barrel Length: 9"
• Barrel Material: 4150 Chrome Moly Vanadium Steel
• Muzzle Thread Pattern: 5/8"-24
• Chrome Lined: No
• Barrel Finish: Black Nitride / Melonite
• Twist Rate: 1:7
• Bolt Carrier: Mil-Spec
• M4 Feed Ramps: Yes
• Muzzle Device: AAC 51-T Blackout Flash Hider
• Gas System Length: Pistol
• Gas Block Diameter: .750"
• Handguard: Knight's Armament URX III Modular Quad Rail, Free Float
• Sights: None
• Suitable for use w/Subsonic or Supersonic loads, either Suppressed or Unsuppressed

IMPORTANT NOTES (From the Manufacturer):

• The 9" and 12.5" AAC 300BLK Uppers are designed for use with a carbine receiver extension, standard GI Buffer Spring, and an H2 Buffer.
• The 16" AAC 300BLK Upper is designed for use with a carbine receiver extension, standard GI Buffer Spring, and a CARBINE Buffer.