I was watching one of the gun shows on Sportsman channel and saw an interesting piece on flinching. You would aim like you normally would with an empty gun, and they put a dummy round on top of the slide, you then dry fired your gun, if you flinched/jerked, the dummy round would fall off the slide and if you didn’t flinch/jerked it would stay there. The way I found out that I flinched/jerked my shot was to have a friend load my revolver and leave a couple of chambers empty, but I didn’t see or know which ones were empty, and when I fired the gun and the chamber was empty, you could plainly see I flinched/jerked my shot.