Even if you do deflect a bullet or slug, I believe the damage caused by a 1oz slug tumbling would be much more satisfatory than a 270win 130gr
A friend of mine used to carry a shotgun loaded with slugs for following up on wounded black bears.I have always used 00 buckshot.After seeing just how easily even slugs can be deflected and how their effectiveness is reduced in heavy brush,he also uses 00 buckshot now.A few pellets may not get through,but enough do to put down any black bear at close range.