GYROJET. I fired two rounds in 1966 from a Gyrojet pistol when Bob Mainhardt and Art Biehl came to an Army Post to test their weapon. No recoil, a slight warm breathe on your hand from the jet, fair accuracy. Really nice guys.
An idea before its time. Too bad.
After 40+ years, one would think that its time might have come by now. :=)