So when did the term GEM come into use? I think this is a GE type 17 or 18. May be a silly question but is that the origin? Gaggenau Eisenwerke .... something..... Though it is always the other way around in German catalogues. I suppose the box could have been made almost any time, it was professionally done nicely dovetailed. Do you know of any original examples?
I see it was called the 'Jewel' http://www.airgunbbs.com/showthread....ing-of-airguns