The Alexander Arms AR-15 Upper Receiver comes fully assembled and ready to install on any standard small pin lower receiver. Chambered in 50 Beowulf, this upper squeezes 50 caliber firepower into a standard AR-sized envelope, offering shooters an immense step up in power compared to a traditional 223 Remington. This upper receiver assembly is an excellent choice for close to medium-range hunting or home defense with it's 16.5" barrel for tight spaces. The upper receiver assembly features a forged 7075-T6 aluminum flat-top receiver for adding optics or iron sights, a free floating handguard, complete bolt carrier group, charging handle and one 7-round magazine. FeaturesThread Protector IncludedTCE Alexander Arms Handguard Direct impingement operating systemOne 7-Round Magazine Included Bolt Carrier Group IncludedStandard Charging Handle