Alexander Arms 50 Beowulf 16inch Chrome Moly Barrel Tactical Upper Receiver 1-20 Twist 49/64x20 Threads Black Anodized. All uppers and rifles are built to order and have an estimated lead time of 10-12 weeks. Please note that using any ammunition that is not factory loaded Alexander Arms .50 Beowulf ammunition will void the warranty on upper receivers rifles and DIY kits. Specifications for Alexander Arms 50 Beowulf 16inch Chrome Moly Barrel Tactical Upper Receiver: Manufacturer: Alexander Arms Caliber: .50 Beowulf Overall Length: 24 in Barrel Length: 16 in Gas System Length: Carbine Length Barrel Twist Rate: 1-20 Threads per Inch: 49/64x20 Finish: Anodized Color: Black Fabric/Material: Chrome Handguard Length: 16 in Gun Rail: M-LOK Gun Make: AR Platform Gun Model: AR-15 Weight: 4.45 lb Condition: New Magazine Included: Yes Package Contents: Alexander Arms 50 Beowulf 16inch Chrome Moly Barrel Tactical Upper Receiver What firearm models does the manufacturer say Alexander Arms 50 Beowulf 16inch Chrome Moly Barrel Tactical Upper Receiver is compatible with? The manufacturer suggests that Alexander Arms 50 Beowulf 16inch Chrome Moly Barrel Tactical Upper Receiver is compatible with AR-15Alexander Arms UTA-50: 50 Beowulf 16inch Chrome Moly Barrel Tactical Upper Receiver 1-20 Twist 49/64x20 Threads Black Anodized