I would use a shotgun with buckshot for leopard, but not a slug.
I would bet money that you CANNOT stop a Cape buffalo charge with a shotgun, especially buck shot, but even a slug does not have the penetration for a head on shot..many a local village poacher has bit the dust using shotguns in Africa, and many a PH has paid the price of stumbling on a buff that has been shot with a shotgun, and was in a nasty mood. In fact on my last hunt in Tanzania Richard Lemmer and his hunter walked up on a bedded cow buff that had been shot in the face with a slug and she turned them both upside down before the hunter shot her in the leg and Richard shot her in the head with a solid out of his .458 Ackley..On that same hunt I saw a buff take a chest shot with my 470 N.E. and another with a 458 Ackley by Lemmer. We traked that bull and lost him only to find him the next day about 7 miles from where we shot him, the lions killed him that night, A buff can take more killing than any animal that I know of..
Again those that have not been there are commenting on things they have no clue about IMO...
