Fed. CC is good, and
http://www.buffalobore.com/ammunition/default.htm#3571850 mv w/180 at above link looks to be a solid performer, should penetrate well.
I'd just be sure to shoot only if I had to, not wait too till a bear gets too close before lead starts to fly and aim true.
Yes, a 45/70 lever, 350 mag, etc. would make me more comfortable if I planned to really need something for a defensive encounter.