XTS Complete Upper Receiver w/o BCG AR-15 300 BO 19.5in 10.5in Pistol 1-8 Twist 5/8x24 Thread M-LOK Bird Cage Black Nitride Finish. With an Anchor Harvey Upper and an XTS Hand Guard this will make your next build the ultimate AR. These XTS complete uppers do not include the Bolt Carrier Group. Specifications for XTS AR-15 10.5in 300 BO Complete Upper Receiver w/o BCG: Manufacturer: XTS Caliber: .300 AAC Blackout Overall Length: 19.5 in Barrel Length: 10.5 in Gas System Length: Pistol Length Barrel Twist Rate: 1-8 Threads per Inch: 5/8x24 Muzzle Device: A2 Flash Hider Finish: Nitride Gun Model: AR-15 Condition: New Fabric/Material: Stainless Steel Gas Block Journal Size-Diameter: .750 in Handguard Length: 10 in Handguard Style: Round Rail Gun Rail: M-LOK Gun Make: AR Platform Barrel Material: 4150 Chrome Moly Vanadium Bolt Carrier Group Included: No Charging Handle Included: MIL-SPEC Weight: 19.3 oz Magazine Included: No Mount Type: M-LOK Country of Origin: USA Package Contents: XTS AR-15 10.5in 300 BO Complete Upper Receiver w/o BCG Anchor Harvey Upper Receiver 300 b/o BARREL 10.5in XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 10in M-LOK Black Gas Block Gas Tube Bird Cage Muzzle Brake What firearm models does the manufacturer say XTS AR-15 10.5in 300 BO Complete Upper Receiver w/o BCG is compatible with? The manufacturer suggests that XTS AR-15 10.5in 300 BO Complete Upper Receiver w/o BCG is compatible with AR-15XTS XTSCUBO10BK: Complete Upper Receiver w/o BCG AR-15 300 BO 19.5in 10.5in Pistol Length 1-8 Twist 5/8x24 Thread M-LOK Handguard Bird Cage Black Nitride Finish Black