I have a Mauser Sporter in 9.3x62 with the initials W.K. on the barrel. It also has the stamp of a K in a diamond, which I assume is the Krupp mark. The initials didn't seem to fit any of the Suhl area gunmakers, so the suggestion of Wilhelm Kruger is interesting. Do you have any other information about this maker?

Do you mind posting a picture of the intials and I can confirm that mine are the same