The Radical Firearms 10.5" M4 Upper Receiver is a flat top, law-enforcement grade, drop in receiver, ready to be mounted to any Mil-Spec AR-15 lower receiver! This fully mil-spec compliant receiver provides a high-quality upper for any level budget or shooter. Comes complete and assembled with Upper Receiver, Forward Assist, Ejection Port Door, Barrel Nut. 10.5" HBAR Barrel and A2 Flash Hider. Bolt Carrier Group and Charging Handle are additional and are offered at discounted prices in the drop down menus.