As a mounted shooter I know that you are constently looking for ways to improve and become better. Most competitive people are. Hopefully this drill from World Chamption Kenda Lenseigne will help you on the pasth to greatness. It was published in Western Shooting Horse Magazine in 2013 (this magazine has since changed it's name to Western Horse and Gun).
This is a drill that I come back to time and time again. It's simple and has lots of great elements for both you and your horse. Hopefully you find it helpful. If you have any questions please feel free to leave a comment below.