German cap and fuze tool

Hi

I found this in the basement of the family farm. The metal box was full of sawdust and detonators (wich I got
rid of, I had to get rid of some old dynamite as well). The box is german, but
is it WW2? Or even military? I have a couple of similar boxes too, just of norwegian
manufacture. When I was in the army in '94 - '95, we had these lessions with
explosives. The detonators we used were german from ww2. They were in wooden
blocks with holes drilled for the detonators.
Can somebody tell me about the markings?
Why the overstamp? Looks like "gmm" stamped on top of "epa".

Thanks.