ABC RIFLE COMPANY AR-15 .300 AAC Blackout Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle Red. The 10in 4150 CMV barrel in .300 AAC Blackout with a 1:8 twist balances control and performance enhanced by a 5/8x24 aluminum radial port muzzle brake for reduced recoil. A steel gas block 9in carbine gas system and locking aluminum barrel nut ensure dependable cycling. Topped off with a full-auto rated nitride BCG forged milspec charging handle and steel milspec ejection port cover and forward assist this upper is built to handle anything you throw at it. Specifications for ABC RIFLE COMPANY AR-15 .300 AAC Blackout Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle: Manufacturer: ABC RIFLE COMPANY Caliber: .300 AAC Blackout Barrel Length: 10 in Barrel Twist Rate: 1-8 Threads per Inch: 5/8x24 Muzzle Device: A2 Flash Hider Gun Model: AR-15 Handguard Length: 10 in Handguard Style: Quad Rail Gun Type: Rifle Gun Make: AR Platform Gas Block Journal Size-Length: .750 in Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Package Contents: ABC RIFLE COMPANY AR-15 .300 AAC Blackout Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle What firearm models does the manufacturer say ABC RIFLE COMPANY AR-15 .300 AAC Blackout Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle is compatible with? The manufacturer says that ABC RIFLE COMPANY AR-15 .300 AAC Blackout Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle is compatible with AR-15ABC RIFLE COMPANY UA300-BR10-QR10-RD: AR-15 .300 AAC Blackout Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle Red