Machine Gun Idea

I had an idea for the class III guys. Why don't they take there existing hand guns and put solenoids on them? If the solenoids were wired in parallel to a switch that connects the slide and frame (electronic sear) and from that connected to a switch for an electronic trigger then on to the batteries, they could have a very fast, cheap, easy to build machine gun! It would only be for the Class III guys though because I believe it would be illegal for anyone else to try it in america. So if you're not class III don't make it. The two contacts (one on the frame, one on the slide) would only connect when the slide is completely forward. When the slide is blown back these contacts would disconnect thus releasing the solenoids and resetting the mechanical trigger. Then when the slide came back to full forward position, the trigger would fire again and continue firing until the operator released the second switch (the control switch). With the batteries in there pocket and a trigger switch mounted on the gun, they will have a machine gun very cheaply! But again I'm sure this takes a special license so I nor anyone should ever attempt to make this novel idea.