ABC RIFLE COMPANY AR-15 7.62x39mm Micro Pistol Build 5in Barrel 4in M-LOK Handguard Upper Receiver Flat Dark Earth. It features a 5in 4150 CMV barrel chambered in 7.62x39mm with a 1:5 twist for improved stability and energy. A .750 low-profile steel gas block and 5 3/16in stainless steel micro gas tube support reliable short-barrel cycling. A 5/8x24 aluminum flash can directs blast forward for enhanced control. Includes a full-auto rated nitride BCG with 9310 bolt mil-spec charging handle forward assist and ejection port cover. Comes with a buffer kit and A2 pistol grip. Lower receiver not included. Specifications for ABC RIFLE COMPANY AR-15 7.62x39mm Micro Pistol Build 5in Barrel 4in M-LOK Handguard Upper Receiver: Manufacturer: ABC RIFLE COMPANY Caliber: 7.62x39mm Barrel Length: 5 in Barrel Twist Rate: 1-10 Threads per Inch: 5/8x24 Muzzle Device: Muzzle Diverter Flash Can Fabric/Material: 6061 Aluminum Handguard Length: 4 in Gun Rail: M-LOK Gun Type: Rifle Gun Make: AR Platform Gun Model: AR-15 Barrel Material: Steel Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Package Contents: ABC RIFLE COMPANY AR-15 7.62x39mm Micro Pistol Build 5in Barrel 4in M-LOK Handguard Upper Receiver What firearm models does the manufacturer say ABC RIFLE COMPANY AR-15 7.62x39mm Micro Pistol Build 5in Barrel 4in M-LOK Handguard Upper Receiver is compatible with? The manufacturer suggests that ABC RIFLE COMPANY AR-15 7.62x39mm Micro Pistol Build 5in Barrel 4in M-LOK Handguard Upper Receiver is compatible with AR-15ABC RIFLE COMPANY ARPK762-ML4-FDE: AR-15 7.62x39mm Micro Pistol Build 5in Barrel 4in M-LOK Handguard Upper Receiver Flat Dark Earth