AR15 Assembled Upper Receiver by Aero Precision The AR15 Assembled Upper Receiver 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 Includes: • AR15 Assembled Upper Receiver in Anodized Black• Includes port door and forward assist