This is a Aero Precision Upper known as the Stripped Upper, model APAR501603C.
Manufacturing a great receiver isn't just about what the end product looks like. It's about what it feels like" how it works" how it handles and performs. Aero Precision products have been recognized across the country by members of the military and law enforcement communities for a simple fact - they work better.
Features:
Precision machined
M4 feed ramps
Mil-spec