What is meant by an "ammunition cook-off"?

An "ammunition cook-off" refers to the unintended ignition of ammunition due to high heat exposure. This phenomenon occurs when ammunition is subjected to elevated temperatures, which can lead to the propellant inside the cartridge becoming hot enough to ignite without an external spark or firing mechanism. This situation is particularly dangerous as it can lead to uncontrolled detonations, posing a significant risk in environments where ammunition is stored or transported under extreme temperature conditions.

Understanding cook-off is critical for safety in both military and civilian contexts, especially when dealing with large quantities of ammunition or in situations where equipment may malfunction or be exposed to heat sources. The other options, while related to ammunition handling or testing, do not accurately define the concept of a cook-off as it pertains specifically to the thermal ignition of ammunition.