I have been using a thrower for clay pigeons. It will throw a 12" disc made out of 2" Styrofoam insulation. Trimmed down one side of the disc so that it would fit into the thrower. Attached a pulley and a rope so that I can trigger it with my foot from a distance. Now all I have to do is get to where I can hit it consistently. Its a lot of fun.
This picture shows how I trimmed the disc so it would fit. The black tape is because I trimmed it to narrow to start with and had to use the tape to tighten the fit up.