[HerrKaiser]

I can tell you that it’s been re-blued/buffed or otherwise constructed of miscellaneous parts, the toggle link on top should have the DWM scroll on it if it’s an original. While carbines like this were sometimes made in 9mm, most were chambered for .30 Luger instead. I see several forum members who take one of their shooter grade Lugers and convert it into a carbine as a project with a great deal of time and effort expended in the process. If I have my guess, I’d say that’s what happened in the case of this carbine.