Stopping power

ability of a firearm or other weapon to cause enough ballistic trauma to a target to immediately incapacitate the target

Stopping power is a way to measure how powerful a firearm is. Stopping power is a measure of how quickly the gun kills an animal, for instance. Many large animals are not killed after being shot with an ordinary gun and can do damage before they die. Elephant guns, which have much more stopping power, are used to kill the large animal quickly.