Sweet is the operative word here; that it is. An over all picture would be nice so we could see how the front end was handled. If I was to wager, I would say it was probably originally an 8.15x46R. This was a popular schuetzen and stalking rifle cartridge. The folks over on ASSR recommend using 32-40 load data. I would slug the bore and do a chamber cast so you can be certain. You might want to cross post this in the German Gun section of this site. Those folks are equally helpful and will probably want some clear pictures of the marks to decipher them for you.
Nice looking little gun, I bet it would be a pleasure to carry after whitetail in the woods.
Thaine
