If legal and there was a very special circumstance involved, I think someone could come up with a dangerous game weapon less than 9.3/375hh.
God forbid, you had a child that wanted to do it as a dream of theirs and they had a life threatening illness, etc. There would be solutions to that including muzzle brakes and some clever calibers to get it done if a "proper sized" caliber wasn't medically/physically possible. (e.g. 35 whelen, 8x68s, etc.)
But for a grown adult that can figure this out, the 9.3x64 / 375HH minimum in most countries is just that, a reasonable minimum. Less is sufficient often, more is occasionally necessary. Put another way, 80% of the time they work every time.
In the end, probably the softest legal recoil solution that will drop buffalo with utmost sincerity would be a .404 Jeffery loaded with a slow burning powder that reduces the recoil even more with perhaps an all copper bullet that you could load down with a few less grains on powder and get the same velocity as the 400-450gr loads. (RL15?) You could probably get the recoil down to 35-foot pounds of felt recoil whereas the standard loading and average guns in 404 put it at 38-42lbs of felt recoil.
God forbid, you had a child that wanted to do it as a dream of theirs and they had a life threatening illness, etc. There would be solutions to that including muzzle brakes and some clever calibers to get it done if a "proper sized" caliber wasn't medically/physically possible. (e.g. 35 whelen, 8x68s, etc.)
But for a grown adult that can figure this out, the 9.3x64 / 375HH minimum in most countries is just that, a reasonable minimum. Less is sufficient often, more is occasionally necessary. Put another way, 80% of the time they work every time.
In the end, probably the softest legal recoil solution that will drop buffalo with utmost sincerity would be a .404 Jeffery loaded with a slow burning powder that reduces the recoil even more with perhaps an all copper bullet that you could load down with a few less grains on powder and get the same velocity as the 400-450gr loads. (RL15?) You could probably get the recoil down to 35-foot pounds of felt recoil whereas the standard loading and average guns in 404 put it at 38-42lbs of felt recoil.