No practical difference. I like both and use both. I prefer the Whelen for smaller large game species because there are more lighter lighter bullets available. For the heavier stuff I like a 9.3x62 with its trademark 286.

I have shot both and I like both, but a 26" barrel 9.3x62 will best the 35 Whelan by a good deal according to my chronograph in that it will handle a 300 or 320 gr. bullet at 2400 plus a tad of velocity and none of the Whelans I had would come near that in the same barrel length, nor can they handle the bullet weight..The 9.3x62 IMO compares more favorably with a .375 H&H with 300 gr. bullets, both on paper and in the field..

The 9.3 case has 7 to 8 grs. more water capacity according to my scales unless one uses blown out 30-06 cases which I don't do as they lack powder capacity, but they do work...

But this is no condemnation of the 35 Whelan, its a fine round in its own backyard....

I think alot of it comes down to better bullet selection for the .366/9.3 than .35. Also, though the Whelan's been arround for a long time as a wildcat, the 9.3s have been arround as factory loads in at least two popular catridges for about 100 years, just more expereince/research went into the bullets I think. Also I think the 9.3s in 286gr. have a better sectional density than the .35 in 250, but I could be mistaken.

Also, I think it has something to do with the fact that the 9.3x62 has been popular in Europe for a long time, and it was THE African all arrounder for many years before the 375. Its really only been "discovered" here in the States recently. So its been pretty easy for companies like CZ (or the double makers for the 74) to export stock here. Lots of companies had experience marketing and selling the rifles and ammo, all they needed was to start selling here. There were plenty of experience with the cartridge in Europe and Africa etc.

While the Whelan has sort of putted arround, having its stalewarts, its not ever really been that popular, though its a fine cartridge. Even when Remington started making rifles and factory loads it never really took off. Not too many other manufactures really seemed that interested in making loads and rifles, no writer adopted it like O'Conner did with the 270 etc. Kind of like the 280, another great little cartridge thats never really took off.


Just some thoughts...