I don't know anything about buckshot on leopards, but know for a fact, they are garbage on black bears and a laughing sotck on grizzlies.

I would think a good pump-gun with fosters would work well on leopards. M870 or Mossberg 535 with someone who knows how to use it is what I'm referring to. Trouble is, that takes practise, which most people won't do today. 3 aimed shots just under 2 seconds is what can happen, but it takes training.

Autoloaders are too slow as fast shots cannot be aimed as with a pump.

Ruger .44 autoloader would probably be a good one- few around, though.