This Advanced Armament Corp. AR-15 Upper Receiver Assembly in 5.56 NATO 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 1 in 7" twist rifling, M4 feed ramps, a 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 1/2"-28 pitch for easy installation of a silencer, and is topped off with an effective AAC 51T Blackout flash hider.
The upper features a forged M4-Style flat-top receiver onto which a Knight's Armament free floating URX 3.1 Quad Rail System is rigidly attached. 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 16" 5.56 NATO upper utilizes the versatile Mid length gas system, a good choice for this cartridge if various weights and types of ammunition are to be used.
- Upper Receiver: A3 Flat-Top
- Barrel Length: 16"
- Barrel Contour: Medium
- Barrel Material: 4150 Chrome Moly Vanadium Steel
- Muzzle Thread Pattern: 1/2-28 TPI
- Chrome Lined: No
- Barrel Finish: Black Nitride / Melonite
- Twist Rate: 1 in 7"
- Chamber: 5.56 NATO
- M4 Feed Ramps: Yes
- Muzzle Device: AAC 51-T Blackout Flash Hider
- Gas System Length: Mid Length
- Gas Block Diameter: 0.750"
- Handguard: Knight's Armament URX 3.1 Quad Rail, Free Float
- Sights: None
- Bolt Carrier Assembly Included: Yes
- Bolt Carrier Type: Mil-Spec, Nickel Boron Finish
- Suitable for use with 5.56 NATO ammunition, either Suppressed or Unsuppressed
- Compatible with all standard AR-15 magazines, including Magpul Pmags (Not Included)
- 5.32 lbs
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.