What is a cookoff in relation to mortars?

A cookoff refers to a situation where one or more explosive components of a round that is chambered in a hot weapon initiate due to the heat of the weapon itself. In the context of mortars, this phenomenon occurs when the temperature reaches a critical point, often due to prolonged firing or inadequate cooling, causing the propellant within a round to ignite without a trigger being pulled. This can pose significant safety risks, as it can lead to unintended discharge of the weapon and potentially injure personnel nearby. Understanding this concept is critical for operators to ensure safety procedures are followed, particularly in managing the cooldown periods and handling of rounds in high-temperature environments.