C'mon, guys!
Consider that pattern density kills, not shot size.
Peter Hathaway Capstick may not have been THE consummate authority, but for sorting out wounded leopards, he claimed that #1 buckshot was (ahem!) the "cat's meow"!
And you also have an equal amount of well known PHs (Robin Hurt comes to mind) say buckshot will get you mauled or even killed against leopards (it happened to him).