Perhaps a dozen of these specialized guns were made in Nazi Germany. They fired either a .32 caliber or .22 rimfire cartridge and had a four-round magazine. At the link, you'll find a copy of a short article from a 1954 issue of American Rifleman about two such guns that had come into the possession of the then-Governor of Alabama.
Link via Hell in a Handbasket | Photo: James R. Rummel
These guns look like some fancy gadget out of movies like "Sky Captain and the Word of Tomorrow" or "Rocketman". :-)