Since I started shooting the 9.3x62 over a decade ago I've hardly used my .375 H&H.
Handloaded to modern .30-06 pressure of 60,000 psi, the 9.3x62 will get aroiund 2500 fps with 286-grain bullets and 2650 with 250's. These loads shoot just as flat as 300 and 270-grain loads in the .375 H&H, and kick noticeably less than the .375 H&H and a LOT less than the .375 Ruger, even in my 8-pound rifle.
I've taken a pile of game up to over 1000 pounds in both North America and Africa with the 9.3x62, at ranges out to 300+ yards, and would be perfectly willing to shoot to 400 with the 250-grain load, since it shoots just about as flat as the 180-grain .30-06, which I've used quite a bit at 400+. And as Phil pointed out, the typical 9.3x62 holds 5 rounds in the magazine, not the 3 of either the H&H or Ruger .375.
This doesn't mean I'm going to sell my .375, but the 9.3 sure has cut into the times I hunt with mine.
