Mmm, reality is that you cant actually gauge performance on paper and sometimes things work the opposite to what one might think. eg , both the 9.3 x 64 Brenneke and the 375H&H (moderrn loads, not original) had reputations as "bullet eaters", especially on heavy bones - like elephant heads , for example. The 9.3 x 64 has pretty much disappeared but the 375 H&H has remained, and the problems of bullet fragmentation , fishtailing, etc continued. (You can find reports in old copies of a few African hunting mags).
Don Heath ("Ganyana") discovered that the the problem could be cured by reducing the muzzle velocity of the 375 H&H by about 200fps, bringing the cartridge back to its original spec. He was also a big fan of the 9.3 x 62, which has never been known as a bullet eater. Few people have had the amount of real life experience that he had, so that is my point of reference. (Note that current 9.3 x 62 performance is pretty much exactly the same as original 375 H&H spec, which is what the 375 built its fame on.)
The tendency here now is to load the 375H&H with heavier bullets (350-380gr) for big game applications. This reduces velocity at the same time increasing penetration. So loaded the 375 is not far off the .416 Rem. - which is my preferred calibre for dangerous game - but now I am getting a bit off Piste.
As far as the 35 Whelan is concerned, it is basically unknown on this side of the pond, so I am not aware of any reports of its performance. Also, it is not legal for use on dangerous game in any country that I am aware of.
I should add that a lot of this minimum calibre thing is a bit misguided and actually based on the performance of cartridges and bullets prior to the second world war (or earlier). I say this specifically because the reality is that the .338WM (a smaller calibre than the 9.3 but a more powerful cartridge) actually does a fantastic job on buffalo, hippo, etc (no reports about elephant but I cant imagine there would be a problem, especially with a brain shot). In fact the only problem that it exhibits is "over penetration" - as in maybe getting two buffalo with one shot (which has happened).
Modern monometal bullets have also significantly affected the potential of old cartridges, turning them into completely different animals.
It should also not be forgotten that many elephants were taken with the humble 7 x 57 Mauser - notably by "Karamojo" Bell, but he was not alone in this.
So the reality is that these minimum calibre restrictions could do with a total review.
Food for thought.
