I've got a Gew 88, it is marked with the 'S'.
I never got around to loading for it (too many more appealing loadings to work with). I figured that nice soft lead loading would be best for it. I would council you think strongly of lead loads.
http://thefiringline.com/forums/atta...1&d=1361475449
Mine is marked with the date of 1890 and armory dated 1914 and Turkish marking to boot. As good a Mauser's steel may have been, I'm chicken. Black powder weapon that is over a hundred years old, light/nice lead loadings and then with slower (more push than pop) powder.
Load with care,
OSOK