That's pretty sick. How well did the 98 fit inside there? Did you have to chop it up quite a bit? I've done a drop in job before and had to shave down both the marker and the stock I was fitting it in quite a bit. The more of these custom builds I see, the more I'm inspired to tackle a full auto P90 build.
Took quite a bit of milling on both the inside of the shell and the outside of the 98, but finally got er' in there. The handle and fwd grip were removed. Everything locks up tight on this one.