Wilson Combat Billet Upper $189

The Billet-AR upper receiver set is 100% machined in the USA and was
engineered from the ground up to address structural design weaknesses in
standard USGI receivers and enhance overall tolerances. It has a
precise bolt raceway for smoother chambering, more rigid receiver walls
to reduce firing flex. The Billet-AR upper receiver is CNC machined from
7075-T6 aerospace aluminum billet stock with a top Picatinny rail,
M4-style extended feed ramps, and smooth side profile without forward
assist for maximum accuracy potential.