That is exactly what I am saying. Grizzlies and especially Kodiak/Polar bear require a little more penetration, so I would use a well constructed expanding round (but hard cast or solids could be used), something like a Swift A-Frame would be best IMO. In fact that is exactly what I intend to use for my big bear rifle (though it is a .375H&H), first shot 300gr. A-Frame, subsequent shots 350gr. Woodleigh solids (for a quartering shot if necessary). Keep in mind these are for a smaller caliber, you will need a heavier bullet to achieve similar sectional density and therefore penetration, so I would use 450-465gr. (heavier will work, but you loose too much velocity) projectiles. I believe that something like the 450gr. A-Frame followed by the 450gr. Barnes Banded Solid would be ideal. FWIW, these are the same bullets that I plan to use in my buff. duster (chambered for .458 Am. Express).About ammo, are you saying that for black bear the Leverevolution(that word is very hard to type by the way!) is good enough, but something more potent is better for big brown bears, etc.?