If may offer one insight on the subject :
During the span of my career ( 1962 - 1970 ) , l noticed that the .375 Holland and Holland magnum and the 9.3 millimeter mauser were two calibres which roughly competed for the same place , in a gentleman's battery : The medium-heavy bore rifle . While American and English sports men favored the .375 Holland and Holland magnum cartridge , continental sports men favored the 9.3 millimeter mauser.
Now , on to the technical aspect of this cartridge. The .375 Holland and Holland magnum uses 300 grain bullets ( although even heavier bullets are now available I recent times ) . The 9.3 millimeter mauser uses a 286 grain bullet. It is not much of a difference , but in terms of performance there is still a difference none the less. While there is very little which a .375 Holland and Holland magnum cartridge can do , which a 9.3 millimeter mauser cartridge cannot do , the 14 grain heavier bullet of the .375 is added insurance . The recoil of the 9.3 millimeter mauser is slightly less than the .375 Holland and Holland magnum cartridge , this is of no consequence , since any man of average strength can fire a .375 Holland and Holland magnum calibre rifle with fair ease .
In regards to dangerous animals , my humble observations show that , for a Royal Bengal tiger , the difference between the 9.3 millimeter mauser and the .375 Holland and Holland magnum cartridge is imperceptible. The same applies to boars and Asian sloth bears .
It is the bison or buffalo which really let's shooters see a difference in terms of the terminal effects of both the cartridges.
Even though l have no direct experience with the African species of cape buffalo , l can put a word about the effects of these two cartridges on the Indian Gaur Buffalo which , l believe is fairly similar with a weight of anywhere from 1500 pounds to 2000 pounds ( for a full grown adult male ) .
A .375 Holland and Holland magnum cartridge , with proper shot placement could take even the largest Gaur from stem to stern and even stopped a few charging Gaurs .
Now , a 9.3 millimeter mauser cartridge was also used by my clients to hunt numerous Gaurs . However , l noticed that if a Gaur above 1800 pounds in weight decided to charge , then the 9.3 millimeter mauser cartridge fared marginally at best for frontal shots.
This , combined with the fact that in most places of Africa , the .375 Holland and Holland magnum is the smallest cartridge legally permitted for dangerous animals , leads me to believe that if a gentleman on a budget is choosing one rifle between the two , the .375 Holland and Holland magnum calibre rifle will benefit him.
