G&G Upper Receiver Compatibility.

[d.j]

I have a G&G M4 metal upper, and I need a metal lower for it. Only thing is G&G metal lowers don't seem to be available like SRC, KA, or G&P. So I can either wait until one pops up in the classifieds or, modify another company's lower to fit. I went on 007 airsoft and noticed the SRC lowers, I also checked out a lot of the local online retailers and from what I see they only sell full bodies. So I was wondering if anyone has done this specific mod to make the two work, and how much work is involved?

I'm pretty savvy mechanically, so I'm not too worried about modifying the receiver I just want to know what I'm getting into before I buy anything.

Also buying a whole new body is out of the question, because I pretty much have everything I need to build my M4, all G&G brand.