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. Upper does not have an ejection port door.
- 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.