The AR15 Assembled Upper Receiver Black comes with the port door and forward assist already installed. Forged from 7075-T6 aluminum, this assembled upper is precision machined to mil- spec M16/M4 specifications and features M4 feedramps. Match this upper with one of our AR15 lower receivers for a solid and dependable fit. Features: M4 Feedramps .250 takedown pin holes Laser engraved T-marks Includes port door and forward assist