The Radical Firearms 300 Blackout HBAR 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 Forged Upper Receiver, Forward Assist, Ejection Port Door and Barrel Nut. These uppers also come installed with Radical Firearm’s FGS Free Float handguard, which features QD points at various points along its round exterior. Barrel is machined from 4150V chrome moly steel, melonited, has a 1- twist & is chambered in 300 Blackout. Upper & barrel feature M4 feed ramps. A2 flash hider is attached via 5/8-24 threads. Pistol length gas system. DOES NOT INCLUDE BOLT CARRIER GROUP OR CHARGING HANDLE.