Thanks kuduae,

I stand corrected then. My friends little 10.75 was definitely based on the MB case. I actually bought one back here to NZ on my return from Germany but have since given it to a collector. I still have the data written up for all the reloading we did for the various calibers we were loading for and I have the cartridge written down as 10.75x47G. His old double did not appear to have been altered so only assume the cartridge was correct. I can't recall if the cases were headstamped.