The upper features a forged M4-style flat-top receiver onto which a KAC URX rail is rigidly attached. The URX creates a full length top rail surface when matched with the flat-top upper to accommodate almost any desired sighting arrangement. The heat-treated, full auto bolt carrier is finished in a slick Nickel Boron coating, and comes equipped with a properly-staked gas key and Carpenter 158 steel bolt assembly. This 12.5" 300 Blackout upper utilizes a pistol length gas system and is compatible with most subsonic and 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.
- Upper Receiver: A3 Flat-Top
- Barrel Length: 12.5"
- Barrel Contour: Medium
- Barrel Material: 4150 Chrome Moly Vanadium Steel
- Muzzle Thread Pattern: 5/8"-24
- Chrome Lined: No
- Barrel Finish: Black Nitride / Melonite
- Twist Rate: 1 in 7"
- Chamber: 300 AAC Blackout
- M4 Feed Ramps: Yes
- Muzzle Device: AAC 51-T Blackout Flash Hider
- Gas System Length: Pistol
- Gas Block Diameter: 0.750"
- Handguard: KAC URX rail
- Sights: None
- Bolt Carrier Assembly Included: Yes
- Bolt Carrier Type: Mil-Spec, Nickel Boron Finish
- Suitable for use w/Subsonic or Supersonic loads, either Suppressed or Unsuppressed
- Compatible w/standard AR-15 magazines, including Magpul Pmags (Not Included)
Please Note: An “AR-15 Pistol” upper assembly has a barrel less than 16” in length. Pistol uppers are only for use on AR-15 pistol lowers and legal Short-Barreled Rifles. Other configurations may violate Federal law.
Please Note: Installation of AR-15 upper assemblies with certain features including, but not limited to: flash hiders, bayonet lugs, and threaded muzzles may violate state and/or local laws.