Regardless if its your first or fiftieth, a Radical Firearms AR pistol will not disappoint. The M4 Profile 5.56mm AR Pistol uses MIL-STD Upper and lower receivers along with Radical's 10" RPR free float rail system for increased accuracy, keeping your hands cool, and giving you plenty of room for accessories. It features a SB-Tactical SBA3 5 position adjustable pistol brace.