No, that's not a 9mm handgun you're looking at, but a 16mm still-image camera. The Japanese-based Doryu Camera Company made the Doryu 2-16 from 1954 to 1956, according to Camerapedia. The Doryu 2-16 was apparently a police-issue device in Japan, and to make it seem even more like a gun, you'd load the camera with magnesium bullet cartridges and then just point, aim, and fire. The magnesium cartridge wouldn't discharge out the "nozzle," but come out the top and act as a flash for the camera; it would also make a large bang in the process. Very cool design, but something tells me you wouldn't want to be snapping pics near any national monuments with this thing.
Doryu 2-16 models are now extremely rare and valuable. In 2001, one specimen sold for close to $25,000 at Christie's auction house in London.
Image credit: Novacon.com.br