This Alexander Arms AR-15 Pistol Upper Receiver comes fully assembled and ready to install on any standard small pin lower receiver. Chambered for the awesome 50 Beowulf cartridge, this upper squeezes 50 Caliber firepower into a standard AR-sized envelope, offering shooters an immense step up the power scale compared to a traditional 223 Remington. This upper's Super Short 12" Barrel makes for an extremely compact and maneuverable package, instantly transforming any Legally Registered Short Barrel Rifle (SBR) or Dedicated Pistol lower receiver into the ultimate close-range fight stopper. Features include a Forged 7075-T6 Aluminum Flat-Top Receiver for adding optics and/or iron sights, 2-Piece Carbine-Length Polymer Handguards, a Picatinny Rail Gas Block, complete bolt carrier group, charging handle, one 7 or 10-Round Magazine and an effective, helically-ported Pepper Pot Muzzle Brake that decreases felt recoil upon firing by as much as 30 percent.
- This upper comes equipped with a Forward Assist and Brass Deflector Only. For increased reliability, the ejection port has been enlarged in order to give the larger 50 Beowulf cartridge cases room to eject. As modified, this upper does not accommodate or include an ejection port door.
- Barrel diameter under the handguard is 0.980", tapering to 0.907" under the gas block, and finally tapers down to 0.775" at the muzzle. The Single Rail Gas Block is proprietary to the barrel's unique 0.907" Outside Diameter.
- When installed on a Registered NFA Lower Receiver, use of a Fixed Stock or Durable Collapsible Stock such as a MagPul UBR or ACE Hammer is recommended due to the 50 Beowulf's recoil.
- Upper Receiver: Modified A3 Flat-Top (No Ejection Port Door)
- Barrel Length: 12"
- Barrel Contour: Heavy, Tapered
- Barrel Material: Chrome Moly Vanadium Steel
- Muzzle Thread Pattern: 49/64"-20
- Chrome Lined: No
- Barrel Finish: Parkerized
- Twist Rate: 1 in 20"
- Chamber: 50 Beowulf (12.7x42mm)
- M4 Feed Ramps: No
- Muzzle Device: Pepper Pot Muzzle Brake
- Gas System Length: Carbine
- Gas Block Diameter: 0.907"
- Handguard: 2-Piece Polymer w/Heat Shield, M4-Style
- Sights: None
- Bolt Carrier Assembly Included: Yes
- Bolt Carrier Type: 50 Beowulf Compatible Carrier
- Includes Single Rail Gas Block, 7 or 10-Round Magazine
- Weight: 4.8 lbs
- Upper does NOT have an ejection port door
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.
Alexander Arms supplies either a 7 or 10-Round magazine with this upper receiver assembly. Sorry, no choice in magazine. Not available in areas where 10-round magazines are prohibited.