I own, load for and shoot various rifles in all the three chamberings and I agree with BFaucett, there really is little difference between them with the best loads.
Seems to me, that we have gone full-circle on this one, everyone has THEIR favourite and using what you shoot best is probably the wisest course of action. But, it's fun to speculate and discuss this as it "could" happen to anyone of us hunting in a fairly large section of North America....and I am GLAD that Grizzlies are still numerous enough that this can be a legitimate concern for us.
