Hello Rhodes,

the Germans designed the 9,3x70 before WW2.
But it seems that the 9,3x64 was enough for the european game and used the standard length Mauser 98 system.
So the ballistic gain was small, but the needed substantial effort.

Reimer Johannsen in Germany offers today a 9,3x70 based on a 98 Magnum system, but the rifle is quite expensive.

best regards
Rolf