TacFire 5.56x45mm NATO AR Build Kit AR Platform 7.50in Barrel Right Black. 56x45mm NATO 7.5in Barrel (1) Bolt Carrier Group (1) Mil-Spec Upper Receiver (1) Slim Free Float MLOK Hand Guard 7in (1) Complete Lower Parts Kit (1) Standard Receiver End Plate (1) Mil-Spec/Commercial Castle Nut/Steel (1) Mil-Spec Pistol Buffer Tube/Alum. w/Foam Cover (1) Heavy Buffer (1) Buffer Tube Spring (1) Mil-Spec Charging Handle (1) Dust Cover (1) Forward Assist (1) Thread Flash Forwarder Specifications for TacFire 5.56x45mm NATO AR Build Kit: Manufacturer: TacFire Caliber: 5.56x45mm NATO Barrel Length: 7.5 in Barrel Profile: M4 Gas System Length: Pistol Length Barrel Twist Rate: 1-8 Threads per Inch: 1/2x28 Handguard Type: Free-Float Muzzle Device: A2 Flash Hider Color: Black Gun Model: AR-15 Fabric/Material: Steel Gas Block Journal Size-Diameter: .750 in Handguard Length: 7 in Handguard Style: Quad Rail Gun Rail: M-LOK Gun Type: Rifle Gun Make: AR Platform Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Weight: 6 lb Magazine Included: No Hand: Right Package Contents: TacFire 5.56x45mm NATO AR Build Kit What firearm models does the manufacturer say TacFire 5.56x45mm NATO AR Build Kit is compatible with? The manufacturer suggests that TacFire 5.56x45mm NATO AR Build Kit is compatible with AR-15TacFire SSPK556LPK: 5.56x45mm NATO AR Build Kit AR Platform 7.50in Barrel Right Black