There are good bullets for use in both sizes, but the over-view suggests the 35 has more bullets available for easy expansion and the 9.3 has more with thicker jackets and offering and deeper pentation. But that not a limitation on either one. There are "very soft" 9.3s and some "very tough" 358s. So take your pick. Both will cover the bases just fine.
The 9.3X62 has a slight lead in power as a rule, but in the game field I doubt that an animal exists that could tell the difference between the 2. The 9.3s do have heavier bullets available and I like what I have used, but I can't say from experience that a 250 grain Partition or Solid Expanding 35 cal would not work just as well.
I own a 9.3X62, but I think all I ask of it could be done as well with a 35 Whelen. If an upgrade in power was needed I doubt a 5% or 7% upgrade would be adequate. If you need more power than you can get from a 35 Whelen you probably don't need a little more. You need a LOT more.
If I need more power then I can get from my 9.3X62 (or, if I owned one, a 35 Whelen) I think it's likely I would jump to my 404 Jeffery or even a 458 Winchester. In N. American I see no such eventuality being realistic.
Last edited by szihn; 01/15/21.
