That is the name of the drill. It is designed for firearms but there are ways to do it with airguns, you just have to be creative and maybe use a second gun. Here is the firearm version. Extrapolate.
IT TAKES TWO PEOPLE.
The assistant stands behind the shooter with the rifle. The assistant operates the bolt and may or may not chamber a bullet and then hands the rifle to the shooter who has no idea if the rifle is loaded or empty. The shooter then shoulders the weapon and attempts to shoot the target downrange. Either way it is a surprise. Good drill.
Tony, we'll do that one with the Daisy 853 this weekend if we shoot together.