RADICAL AR15 7.5″ 5.56NATO pistol with 7″ RPR and SBA3 The Radical Firearms 7.5″ M4 Profile 5.56mm AR uses MIL-STD Upper and lower receivers along with our 7″ RPR free float rail system for increased accuracy, keeping your hands cool, and giving you plenty of room for accessories. Regardless if it’s your first or fiftieth, a Radical Firearms AR pistol will not disappoint! ***PRODUCT MAY VARY DEPENDING ON AVAILABILITY*** Barrel Length: 7.5″ Barrel Thread Pitch: 1/2×28 Chamber: 5.56mm Twist Rate: 1:7 Gas System: Pistol Length Muzzle Device: A2 Flash Hider Handguard Style: M-Lok Thin Rail Handguard Length: 7″ Charging Handle: MIL-STD Buffer Tube: Carbine Buffer Tube Magazine: 1x 30 Round