ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle Olive Drab. The 10in 4150 CMV barrel with a 1:7 twist and radial port muzzle break ensures consistent accuracy. A 6061-T6 aluminum barrel nut with locking steel jam nut 9in carbine-length stainless gas tube and .750 steel gas block provide smooth cycling and reliability. Completed with an MPI-tested nitride BCG forged charging handle and all milspec forward assist and ejection components this upper is ready for range or duty use. Specifications for ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle: Manufacturer: ABC RIFLE COMPANY Caliber: 5.56mm 5.56x45mm NATO .223 Remington Barrel Length: 10.5 in Barrel Twist Rate: 1-7 Threads per Inch: 1/2x28 Muzzle Device: A2 Flash Hider Gun Model: AR-15 Handguard Length: 10 in Handguard Style: Quad Rail Gun Type: Rifle Gun Make: AR Platform Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Package Contents: ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle What firearm models does the manufacturer say ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle is compatible with? The manufacturer says that ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle is compatible with AR-15ABC RIFLE COMPANY UA15-BR10-QR10-ODG: AR-15 .223 Remington/5.56x45mm NATO Pistol 10in Quadrail Handguard Complete Upper Receiver w/BCG And Charging Handle Olive Drab Green