This is a great marksmanship drill that came from David Blinder at personaldefensetraining.com.
Start at 3 yards. You have to get all 50 hits to pass. Once you can shoot the whole drill without a single miss, either increase the distance or add time pressure. For instance, try to finish the entire drill in under 5 minutes while maintaining 100% accuracy.
(click on the target to bring up the full-size version which you can then print out)
There is also a dedicated TDA (Traditional Double Action, aka “DA/SA”) version created by Sean Leffler:
Training with firearms is an inherently dangerous activity. Be sure to follow all safety protocols when using firearms or practicing these drills. These drills are provided for information purposes only. Use at your own risk.