to me everything on this fine rifle looks original

suspect its in 8x57I? you better made a chamber cast and slug the barrel. your rifle was made in Suhl between 1900 and 1914 maybe by Haenel or Schilling.
did you load 8x57I ammo? I have used the 8x57IS RCBS die set just resize the case without the deccaping rod which hold the neck sizer. this give the case an undersized neck and hold the .318 bullet very fine in the end.