DROP on the spot to a chest hit, with 12 ga slugs, .45-70, or 3006 softpoints. They'll tell you (if they are honest) that a very high % of those so hit run a ways, at least. Way too far if they were big bears, attacking you. Do NOT count upon a body hit stopping a big charging critter, because it's unlikely to happen. Unless you hit the spine, the odds of a body hit working for you, soon enough, are very poor indeed, even if you are using a 458 elephant round.