This is a pretty nice reciever. The problems I had were easily fixed and superficial.
Looks pretty sick
Fits Marui Gearboxes.
My old Echo1 parts (Charging handle, bolt release, mag catch, etc) all fit fine, so I didn't have to buy anything.
Comes with everything you need for a FUNCTIONING (holds your gearbox) reciever.
You get what you pay for.
The lower and upper recievers are two different materials.
The paint scratches easily off the upper reciever to reveal an ugly silver aluminum. Buy the black version.
The lower reciever scratches to reveal the black anodized aluminum.
Uses the old-type Classic Army reciever system. Its not compatible with anything other than those and other Madbull recievers, so no mixing or replacements without purchases.
The forward assist was immensely difficult to assemble, required a lot of improvisation for parts.
The pin holes don't fit the included pins well. Forcing them in a few times/dremel work for a short time should fix this easily.
Problems are easily fixed, and it only looks like there's a lot because I want purchasers to know what to expect.