Depends on how much ammo you got. You can take a bear out with the right shot placements, though I wouldn't do this or want this for SD if it was charging me, but say like you are in a tree and it was blocking you from escaping.
SHTF vs TEOTWAWKI you ask? SHTF, just some crap on the ceiling and walls, TEOTWAWKI end of the world as we know it. Orignally made by 9mm/®™©