Mini Gun ?

Really tiny blank firing 'Mini-Pistol'

That's a .45 ACP casing for size comparison.

You've all seen those videos of various mini-guns being fired from helicopters and so forth, but here's a little different mini-gun. I got it sometime in the late 1950's, along with a couple of packages of ammunition. There's no name on it, and "Japan" is stamped on it's side.

The cartridges for it are very tiny copper cylinders with a tiny wire sticking out the side. When you put the round into the chamber, the firing pin wire points straight up through a small slot on the top of the chamber. The hammer is then pulled back to cock it, and pulling the tiny trigger drops the hammer, which hits the detonator pin, firing the round. The barrel is not bored to the muzzle, and there is a outlet port on the bottom of the barrel for the hot gases to exit. The report was amazingly loud, louder than a .22 rifle, as I remember. You could also get a good burn on your finger if you hat in near the exhaust port under the barrel.

Does anyone know any more about this little blank pistol? Is there a source for ammunition out there?