In another thread we had a conversation about what guns are appropriate for Moose and Bears. I'm posting a link to a thread that my brother started about Grizzly Bears. If you read through the post and open the pictures you will see some nice bears and read some expert commentary from a man who has 2 Grizzlys entered in Boone and Crockett, 1 of which is top 50 all time. In the thread he talks about a guy who uses a 30-30 to hunt bears...
http://www.shootersforum.com/showthread.php?s=&threadid=4581&perpage=15&pagenumber=1