it look we are highjacking this post now, its the first 9x63 I have ever heard. this cartridge is for the 9x57 what the 7x64 is for the 7x57.
this is from a 1926 Ernst Steigleder catalog, the cartridge was never realy popular and is allmost forgoten now

it was shooting the same 16 gramm bullet as in the 9x57 but with 780 m/sec instead of the 720 m/sec.
there is also a rimmed version in the list but it's maybe so rare like the 9,3x65R Brennecke
good that you reload- most clever hunter's would recommand to rebore the rifle for the 9,3x63. what a shame!
I hope to see the pics from your rifle