A&K M4 Complete Metal Receiver for Tokyo Marui & Compatible Airsoft AEG Rifles

"Perfect metal receiver, fits a ares gearbox with no modification. cheap piece

"It is a pretty standard receiver that needs some modifications to work. I had to remove some materials inside the front of the lower, where the lower portion of the hopup unit sits, so that the gearbox could be inserted. I also had to remove much of the buffer tube mount to fit a modern buffer tube. this receiver set comes with everything except for the selector plug. bolt catch release, trigger pin, body pins, charging handle, mag catch, and selector switch are all included

Pros:
cheap, sturdy, snappy selector switch, and flush top rail with most aftermarket rails. there is no play between the two halves of this receiver

cons:
needs some modifications and it doesn't include selector plug. selector plug is also proprietary compared to every other manufacturer, even retro arms. mag catch needs some modification to hold mags.

this is a good platform for a cost effective scratch build. i fitted a generic outer barrel and krytac defiance rail with no issues at all.

"Overal the thing is very nice, it is sturdy and well made.
Pros: Full Metal
Hop up support
quality threads

Cons: Extremely difficult to get a gearbox in, you will likely have to make modifications to make it fit.
Once you get it in it is solid but be ready to wrestle with it to get it in place