First let me say that they are both excellent cartridges. The only real field difference that I could think of would be that the heavier bullets in the 9.3 would be better for larger game like big moose or brown bear. The 9.3 does with 286gr bullets what the whelen does with 250. If you loaded them both with a 250gr bullet the 9.3 would have a slight advantage in velosity but the whelen would have better sectional density and probably penetrate better. There is definately a better/more readily available selection of bullets in the whelen. Locally there was only three kinds of bullets for the 9.3, 270gr speer and 286gr Nosler Partition and 250gr Ballistic tip. No brass, and one brand of loaded ammo, norma @ $60 a box. There are two types of loaded ammo for the whelen, federal and remington, and several 35 cal bullets, hornady, nosler,barnes, and speer in weights from 200-250gr. THe whelen is actually fairly popular here in alaska.
I chose the whelen for my dads rifle because he normally hunts in michigan and the whelen is perfectly suited for lower 48 hunting. Its is also pretty good for alaskan hunting too. A good 225 or 250gr bullet at 2600 or 2400fps is good enough for anything that alaska has to offer. Due to 250 being the heaviest I expect to shoot out of that gun I went with a 1 in 14" twist.
For alaska I like the 9.3 because it takes a 286gr bullet at 2450 or 270gr at 2550fps and that little extra power and bullet weight might come in handy for the big bears. The 9.3 has a 1 in 12 twist due to the longer bullets.
Performance on the moose was pretty much to be expected. I was using the 270gr Speer SP @ 2400fps. Its a mild load that shoots really well. First shot was at 270 yards and hit low chest right at the last rib, taking out the liver and edge of lung, I misjudged the range a little. Complete penatration 1/2 entrance and 1" exit. As we approached the moose it started to get up so I shot it a second time as it faced me right in the throat at the base of the head. Surprizingly this bullet didn't exit, It looks like it hit the spine and deflected up into the skull, I did find some bullet fragments right against the spine at the base of the head but very little. The bulk of the bullet must be somewhere in the skull.
Here is a pic side by side of a 225gr whelen and 286gr 9.3x62, both nosler partitions. As you can see the shoulder location is much higher on the 9.3 with shorter neck for about 10% more case capacity.
