I got this gun when my father-in-law passed away a couple of years ago. He had gotten this from his father. He had brought it back from Germany after WWII. He had gotten it off of a German man. We don't know a lot about this gun. I was wondering if anyone has ever seen anything like this. I do know my father-in-law had been offered quite a bit for it at one time. Inscribed on the top of the barrel is A. KORINSKI,ERLANGEN.. I wasn't sure if this was a persons name or a manufacturer. On the back end there are also the initials D.R.G.M.. I'm just looking for any information someone might have about this type of gun. I have pictures attached.