The Impeccable .375 Holland & Holland
When asked by foreign hunters planning a first trip to South Africa which calibre rifle should be brought for non-dangerous game my answer always is: "a 30-06" as it still is the standard against which all else will be judged.
If Cape buffalo or elephant or hippo is to be hunted my answer always is: "a .375 H&H" as it is - and always will be - the standard against which every new kid on the DG block will be judged in Africa.
From personal experience I have never seen a poorly placed bullet from either a .458 Lott, .458 Win Mag, .416 Rigby or a .375 H&H being able to immediately put down anything from even deer size impala, to eland, to Cape buffalo.
I have witnessed 13 well placed shots from a .458 Win Mag failing to put a Cape buffalo down due to lack of penetration, and I have seen wildebeest and gemsbok absorb .300 calibre bullets through the lungs as if untouched. I personally lost a bushbuck in northern Mozambique from a lung shot with the .416 Rigby, and I have witnessed the wound channels on an impala made by four .458 bullets, and only the fifth into the heart put it down.
Similarly, I have never observed a properly placed shot from a .375 H&H, using a properly designed bullet of 300 grain that did NOT break both humerus bones of a Cape buffalo if shot into the low shoulder, cut open the heart, and the animal going down in 50-60 yards as it would do. An expanding monolithic bullet of 300 gr will bulge the opposite skin, and a flat nose solid like the VRG-2 Peregrine will be in one side and out the other side, breaking both shoulders. The .375 H&H is an impeccable performer under all conditions.
On non dangerous game, using 270 gr standard cup and core bullets like the PMP ProAmm (Hornady Interlock) the .375 H&H is as flat shooting as a 30-06 with 180gr, or 7mm Remington Magnum and 175 gr bullets.
I have used the .375 H&H on game from impala to Cape buffalo, and the same with the .416 Rigby. I have seen the .458 Win Mag and the .458 Lott in action on small and big game as well as on the large dangerous species. The .416 Rigby is an impressive cartridge with very little recoil. The .458 Lott is an equally impressive performer with considerable recoil. The .375 has a short duration recoil impulse which is sharper than the Rigby but still totally manageable, and its on-game performance is exactly the same as the two larger chamberings.
This is a photo of a 300 gr PMP ProAmm bullet that had traversed a zebra from the rear end rump all the way to the top of the beast bone - that is almost 5 ft of muscle and sinew - retaining 90% of its weight and creating zero meat damage. For a soft nose, expanded bullet that is impressive penetration.
Below is an example of a Voere .375 H&H belonging to South African hunter Gary: