Re: 100 yd courses of fire!
There was another drill I came across in the Marines that was similar to the dot drill prescribed by ewoaf there.
Basically the same except the dots where of various colors. All and all there was only about 3 different colors but they were spread out over the dots randomly. When you begin the course all shooters stand with 5 rounds loaded in there rifles and there backs to the targets. Range control would yell out a color, and when the command "fire" was given the shooter would turn to the targets go to prone and engage the color that was said within a time limit.
This can be done in many ways; more colors, different shooting postions, shorter time, ect.