hallo felix

no, the DR harald wolf was working for was in the possession of an austrian gentleman from before WW 2, harald told me that he had made ammunition from russian 7,62x54R in the 50s for the rifle. rumanian 6,5x53R ammo would be to small to work, the 8x56R M30 is the best case.
I do not wonder about the confusing who had made now the springer double rifle's. there was a lot of globalisation in the triangle Suhl, Ferlach and Liege hundred years ago.
I am aware that the 10,75x52R wasnt a stopping cartridge. it was made to build light and handy double rifles, maybe similar to the 375 NE 2,5" flanged.
do you have a muzzle velocity for the 16,7 gramm bullet?
do you have an explanation for the "10,75x52R Springer Austrian Navy experimental cartridge" designation in some books? no doubt a mistake that someone started and that was copied again.