Yes I know the 7,65 Luger. Sorry, my english isn't good.
I mean was this 7,62 or 7,65 or 7,63x54 rifle cartridge his own idea to make wildcat that could use same bullets that his 7,65 Luger pistol was using? Or was it some kind of unknown factory design?
Bird hunting has always been popular here in Finland. I can imagine that availability of suitable calibers and full metal jacket bullets was limited before WW2.