“7 and 8 shoot are good for small game, rabbits squirls, not for intruders”
At a short distance, even 8 birdshot will kill. Go out and shoot one into a water filled (or ballistic jell filled) plastic bottle.
Your correct, but the penetration is not that good. If your at point blank range yes, in that case buy the judge, 410 or 45 long colt, stick in there gut and bang.