to Molasses: That does look pretty good. I'll use that.
One final idea I had along the lines of the pistol-sized shot revolver, just in case it could be made to work (I like revolvers for some reason, hard habit to shake.): recoil-less. The extra gas is channeled into two tubes, one on either side of the barrel, were it goes forward almost all the way to the end of the barrel and is redirected out through a slit on both sides that are angled 45° backwards. Held at arms length like a pistol is supposed to be fired at, the two gas jets should miss the shooter. It'd still have some recoil, of course, but maybe not wrist-breakingly so. Stupid idea?