ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Micro Pistol 5in Barrel M-LOK Handguard Upper Receiver w/BCG And Charging Handle Olive Drab. 56 NATO barrel for tight performance in a compact package. Outfitted with a low-profile steel gas block micro gas tube and 7075 aluminum flash can its built for smooth cycling and recoil control. Includes a full-auto rated MPI-tested BCG milspec charging handle and all standard forward assist and ejection components. Specifications for ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Micro Pistol 5in Barrel M-LOK Handguard Upper Receiver w/BCG And Charging Handle: Manufacturer: ABC RIFLE COMPANY Caliber: 5.56mm .223 Remington 5.56x45mm NATO Barrel Length: 5 in Barrel Twist Rate: 1-5 Threads per Inch: 1/2x28 Muzzle Device: Muzzle Diverter Flash Can Handguard Length: 4.5 in Gun Rail: M-LOK Gun Type: Rifle Gun Make: AR Platform Gun Model: AR-15 Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Package Contents: ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Micro Pistol 5in Barrel M-LOK Handguard Upper Receiver w/BCG And Charging Handle What firearm models does the manufacturer say ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Micro Pistol 5in Barrel M-LOK Handguard Upper Receiver w/BCG And Charging Handle is compatible with? The manufacturer suggests that ABC RIFLE COMPANY AR-15 .223 Remington/5.56x45mm NATO Micro Pistol 5in Barrel M-LOK Handguard Upper Receiver w/BCG And Charging Handle is compatible with AR-15ABC RIFLE COMPANY UA15-BR5-ML4D-ODG: AR-15 .223 Remington/5.56x45mm NATO Micro Pistol 5in Barrel M-LOK Handguard Upper Receiver w/BCG And Charging Handle Olive Drab Green