There were no shotguns in that film! The double barrel you were seeing was a Krieghoff double rifle! A full 90% of a wounded leopard getting to the shooters in a charge, the follow-up was done with a shotgun. This is not a common practice, because the PHs have learned over time from the experience of others, that a shotgun is not a good choice for this activity.

I think you would change your tune if you had been the one holding the rifle. A fast moveing Leopard is not an easy target to hit, and harder to stop when you do! The angle in low, moveing fast, and constantly changeing. The lead amount is constantly changeing, and misses are far more common than with larger and slower animals.

As old lion hunters have found, when charged they dropped to their knees, so the angle is the same for the whole charge. This would not have worked in this case because the grass was too high, and a lower shooting position would have hidden the target.

Monday morning quarterbacking is a very easy profession,one everybody is qualified for, but it doesn't pay very well!