Roy Stedman posted these slow motion videos about shot calling back in 2009.

The way to use these videos is to watch the sights, and try to “call” where the shot is going to go based on the visual information you have in the last microsecond before the shot is fired.

This is very difficult to do because we blink frequently (and in reaction to shots being fired). It takes less than 1 millisecond for the shot to go down the barrel, but our eye blinks are 100-150 milliseconds. (On a shooting timer that’s 0.100-0.150.) More about blinking and bullet speeds here

How fast is a blink?

Iron Sights:

Dot Calling #1

Dot Calling #2

Shot calling is a useful skill, but more often than not a shooter’s eyes may be closed as the round travels down the barrel. That’s why dry fire practice, specifically practice developing the skills to press the trigger without disturbing the alignment of the gun, is so critical to shooting more accurately. Even in dry fire, your eyes are going to be blinking. A movement measuring device like the MANTIS can record gun movement and display the data for you to study.

This feedback is not as immediate as observing the sight movement during the dry or live fire shot, but it can be useful in developing correct technique.