That is one old Mauser. I don't know what smokeless loads were being used in 1889 vintage rifles, that is still in the blackpowder era and the metallurgy of the period stunk.
You just don’t know what they did not know, about steels back then, until you study the topic.
Obviously it has been shot with 250 Savage loads, but I would error on the side of caution developing any loads for the thing.
If I'm not shooting, I'm reloading.