ok, i realize this has been talked about on a million forums, and i have probably read half of them. problem is the exact answer never seems to be anywhere. i realize the pkt parts are not interchangeable with pkm parts and some modifications have to be done. however, my question is, if i have a pkm receiver, pkt barrel, and pkt parts kit, what is it actually MISSING? i realize the fcg is going to be one problem and people often fabricate it out of an ar trigger group, but is there even more to it than that? is the whole project even remotely feasible?