There is an article in the Mannlicher Collectors Association news letter last year listing loads for the 9.5x57. The bullets were 235 gr Speer and the 270 gr Hornaday 3715. The powder was 4895. I have been trying to work up a load with WW ball powder, so far I have exceeded what should be a maximum for the Speer 235 gr but no pressure sign, only about 2150 fps. I have 50 years experience with IMR powders but zero with ball powder, I don’t know how forgiving ball powder is.
Mike