Grizzly, Corbon, Garrett, Buffalo Bore & HSM all make suitable "bear loads" in the 400-460gr range. I think HSM is the cheapest of the bunch.
Shooting a bear in self defense is a whole different world than hunting a bear as it will likely be at very close range and coming at you. Maximum penetration and damage is what you're looking for. That being said, I've never had to shoot one in that scenario thankfully so I'll leave the specific recommendations to someone who has.
Practicing shot placement for that situation is invaluable, but it's tough to replicate the adrenaline rush, target speed and timing.
