Gartenmeister,
I suspect a little heavier 38cal cast bullets would work even better than the 148gr.There is a 3 part article on loading the 9.3x72R(and different case lengths by extrapolation)in old German Gun Collectors Assn. publications.If you are a member, you can obtain copies at a club discount.If you are not a member, maybe you should join, you seem to share the interest.
Mike