hello johann

I have found pics of the 10,75x52R Springer in two french books, not under sporting but experimental military rounds. it is described as a cartridge designed for the KuK navy with a full metal jacket, Hirtenberger made in 1908 - very strange!?!
I dont know why the KUK navy would need such a round in this time. the german navy have use of course insert barrels in canons for the 11,2x60R mauser but this was a budget thing for using old ammo stocks .

for all who thinking that the 10,75x68 isn't having enough power here is also a french military load for a squeezed bore riffel