Interesting, I have heard that from a few people. That the .338 Win Mag does not work well on water buffalo. Yet a couple said the 8x68S does work well ... Does not seem logical. Maybe it is something to do with bullet construction?

What is the Best Magnum Cartridge?

To me the one that started it all. Maybe not the "original" but next to no one has heard of a "Veloplex".

The .375 H&H Magnum.

The one and only.

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If one means "magnum performance" rather than a belt, the .375 H&H is hardly a magnum performance cartridge today, but it still does what it is meant to and not badly at all.

Personally I really dislike increasing velocity beyond a certain sort of speed in a bigger bore rifle. Around the 2000 to 2600 fps speed. They aren't meant to be sniper rounds. Most scenarios anyway, and if shooting at soft skinned targets, is a big bore needed or desired?

If one wants more performance than a .375 or 9.3x64, upgrade to a .400 or .416. Want more, go to a .450/.458/.470, more? Go to a .500, then a .577 or .600. After that recovery time is getting really silly. Rather than more speed, a heavier bullet, with greater calibre is what works better.

And greater speed? Very few people buying a .378 Wby or .460 Wby ever consider if the bullets are built for those speeds and reliable expansion and penetration.

Why suffer the recoil for no added benefit?

Now if we are talking about longer distance rounds, we are talking about small to medium sized calibres, IMO.