Since we're showing off tommyguns, here's mine.
The commercial semi auto 1927A1s & M1s cannot be converted to full auto without the services of a full machine shop (which could also build a gun from scratch), as the internals of the semi auto are completely different than the SMG, and the dimensions of the reciever are 1/4" off from the SMG.
Completely milling out the entire inside of the reciever, and then installing the full auto parts would be the minimum necessary, and of course, it wouldn't be legal to do it, even if you could.
Getting one converted to a SBR (short barrel rifle) is much simpler, providing it is legal in your state, and you get BATFE approval BEFORE
you shorten the barrel.
My gun feeds everything I've put in it, FMJ, JHP, LRN and LSWC bullets without any issues from the stick mags. Still haven't gotten the drum to run flawlessly..yet.