Very interesting hammer falling block, caliber 8,2x50R ( the old austrian military caliber).
Barrel signed by Miller & Val. Greiss, " Kruppsch. Gussstahl".
Engraving is an Suhl area work. Maybe the rifle itself is also an work from Suhl or Zella Mehlis.
Mounted on an "Wiener Schnäpper" is an Svarovski Habicht 4x32.