Just for the sake of conversation, the 30-06 has probably taken more grizzly bears than all other calibers combined. Long before the modem magnums, guys like O'Connor were taking polar and brown bears with the 30-06, 270, 7x57 and yes the 30-30 and 30-40 krag. For quite some time, the world record grizzly was one that was killed with one shot from the 30-30. The Natives up north have taken polar bears with everything from the 22 hornet on up and a few Polar and grizzly with the 22 rim fire. Of course this does not make themadequate big game rounds but the 270 and 7x57 Mauser have taken every species of big game on earth and will continue to do so. IMO the 7x57. 6.5x55 and 270 are the most under rated cartridges on earth. All will fire 160 grain bullets and heavier with very good SD and excellent penetration. Add low recoil and the ability of most hunters to place their shots very well with these calibers and you have some pretty effective big game getters.

My main reason for picking the smaller calibers is that 99 percent of my and most other hunters shots won't be at grizzly bears or even in country where they exist. I am not a one rifle for everything hunter but I could make do with these middle calibers quite well. In the end for the big bears I have several 45-70's and I wouldn't hesitate one second to use that for the big stuff.