Original ammo used the standard 8x57 (8mm Mauser) casing, which was invented for this rifle. Original load was with a 227-grain RN .318" bullet.
This was changed to a 154-grain flatbase pointed bullet (Spitzer) of .323" diameter in 1904.
If your receiver is marked with a letter S above the chamber, then your rifle has been adapted to handle the more modern loading.
I shot a Carcano Cavalry Carbine for some time. Finally, my ears could no longer handle the punishment and the 3-foot fireballs were making everyone else nervous, so I stopped using it. Years later I started to THINK instead of just REACT, loaded up some ammo with a very fast powder. Rsult? A nice-handling and fairly accurate LITTLE rifle. No ear-splitting crashes, no fireballs and group sizes shrank dramatically.
I note that the original First World War German ammunition was loaded with rather a quick Flake-type powder. I think that if I owned one of these little treasures, I would be shooting it with something like Reloader 7 or perhaps even experimenting with 4198. Certainly nothing slower than 3031. Fireballs and ear-splitting crashes are powder burning in the AIR; you want it to burn in the BORE.
Hope this helps.
Lovely little rifles, these are.