Trouble with this question is it's usually asked "Best cartridge for BC", then when it's brought up grizzlies can be the size of moose on the north coast, or more plentiful than black bears over everything north of 58 degrees, or that moose on the Yukon border can go 1,500lbs, a bull bison can go 2,600lbs... "Well aside from those, .308 / .30-06 / .280 is perfect."
Province wide, ideally it's a .338 Win Mag, a .300 is great too. A .30-06 will do it of course too, but it is by no means the best. Douglas probably is closest to best with the .340, as he gains some trajectory over my .338 WM nomination, and it certainly isn't going to do worse on the animal is it?
We aren't debating the best cartridge, we're debating our favourite cartridge. Academically there isn't a thing a .30-06 can do the .300 can't improve on. Add human factors like recoil sensitivity, rifle weight and how much the hunter can carry, etc and we're now into preferences that aren't the same for everyone. Moral? .30-06 is not the best, it's just good.[/QUOTE]
Nope, 30-06 isn't necessarily the best, but it's pretty much the max recoil-wise that probably 80% of shooters should use, unless they're prepared to do a lot of practice and acclimatization. 300 mag and up, especially 340 and up is a big mistake for most shooters. I own and love my 340 Weatherby and think that it is without a doubt the best all-round Large Game rifle there is for N. America, but I don't think most hunters should use it.