I carry my 329pd for bears (I know I know pistols vs spray yadda yadda.) But, I always wonder about attaching my revolver to my pack but it seems like I always drop my pack to clean animals, for the stalk and to call..... these also seem to be the times that you are more likely to encounter a bear. So I always go back to a hip holster I can put low on my belt and use with or without a pack. May not be the fastest or best way to draw... but better than having your weapon 100 yards away.
Joe