Determining cook-off time for a weapon is disclosed. A method determines a first barrel temperature next to a first energetic, such as a propellant charge, of ammunition within a gun barrel, and determines a second barrel temperature next to a second energetic, such as an explosive charge, of the ammunition. If the ammunition did not properly fire, the method determines a first cook-off time of the first energetic based on the first temperature next to the first energetic and the first energetic's type, and a second cook-off time of the second energetic based on the second temperature next to the second energetic and the second energetic's type. The first and second times may be determined by using one or more finite-difference heat transfer models. If either or both of the first and second times are less than a threshold, a warning-related action is performed to users of the weapon.