I wouldn't consider either as a back up firearm for an angry bear. Of the two though I think I would opt for the 30-30 with the nasiest bullets you can find for it.

In my opinion both are ok for deer, but that would be my limit, certainly not bear. I consider the 243 to be more of a varmint, small/medium game type weapon.

I would use a 12 gauge slug gun if you have one rather than the two rifles you mentioned.

Just my opinion any way. I don't bear though.

Paul