Doubleup:
It may be a long shot I realize, but check the .43 Mauser (11mm Mauser, or 11.15 x 60 R). If that 10.7 mark refers to bore diameter rather than bullet diameter (ie 'land' diameter prior to cutting the rifling), then this could be it. The 11mm Mauser was a popular sporting cartridge long after it became obsolete as a military round.

Other than that, no definites, sorry.