Greg,
While there are other rounds that are more powerful, the 375H&H is a great one and smacks of nostalgia and history. In the spirit of "cartridge spacing" is about right given what you've already got.
I've used the 375H&H for elk hunting and the results were just "delightful." K-Thump.... plop



It will reach right out there too (of course I'm kind of a 200 yards is easy, 300 is pushing it kind of guy).
If you end up going to Africa, then the 300 RUM, the 375 H&H and a 458 Lott would be an awesome 3 gun battery. You'd be able to find ammo for the 375HH anywhere and in a pinch the 458 Lott will take 458WinMag ammo which is also "common" over there.
Nothing like planning ahead!


Careful though, like has been said elsewhere.... "Once you've kicked up your weaponry a notch and used them and experienced the difference, then it is practically impossible to go back to "the good old days" unless you get too tired, too old, or get injured.