Peter Hathaway Capstick in one of his books(I believe it was "Death in Silent Places&quot talks about this very subject only his quary isa wounded Leopard, considered by most the most dangerous game. He did some research about buckshot and found that the way teh pellets load into a shotshell Number 1 buck has over 1/3 MORE pellets that 00 buck and a diameter of only .03 inches less. .30 vs .33.
He made a very persuasive argument about the uses and non-uses of buckshot including a story about shooting a lion with a number of rounds at 35 - 40 yards and none of the pellets penitrating to do any damage.

From what I have seen and read is you are going to use a shotgun for self defense against a bear it will need to be at very close distance or you are just going to make the bear made and also target the head and not body. IF he can't see you he is going to have a tougher time finding you.

Just my 2 cents



Greg

"Getting close to the game is the joy of Bowhunting for me, the harvest is a bonus."

Live 15 ft Python after eating a small Antelope!