If you go back into the Field & Stream archives far enough, Bob Brister, on a bet, used a Brennke slug to take a Cape Buf. using his Pirazze with no special sights. It's doable if you are up to it.
I read this article myself, many years ago; I forgot the name of the author though. I do remember that the slug broke up. Part of the slug did penetrate the heart and kill the buff. However, it was a short range, broad side shot under perfect conditions. If I recall correctly, the takeaway was that while possible under ideal conditions, the performance wasn't convincing enough to make the practice sensible.
