Your 1885 vintage rifle was built for black powder and should be used with black powder or suitable substitutes. The pressures of the 9.3x74R were not envisioned at the time your rifle was designed or built. If it is as nice as you say, someone (perhaps even me) might trade a nice 9.3x74R rifle for it. (Oops! Didn't notice the Ireland address. Sorry, can't trade.)