Most chronographs consist of two sensors a short distance apart that you shoot a projectile through while the unit is activated. The device measures the time it takes the bullet or other projectile to pass between the two sensors, then calculates the projectile's velocity, generally in feet per second.

How does a chronograph measure bullet speed?

The modern chronograph consists of two sensing areas called chronograph screens, which contain optical sensors that detect the passage of the bullet. The bullet is fired so it passes through both screens, and the time it takes the bullet to travel the distance between the screens is measured electronically.

What is a chronograph bullet?

In a nutshell, a chronograph lets you measure the speed that the bullet leaves the barrel. This information, in conjunction with data about the bullet you are firing and the environment you are shooting in, lets you start mapping out the expected flight path of the projectile.