What type of action should be taken to prevent a runaway gun?

To effectively address the situation of a runaway gun, the correct action is to grasp the cocking handle and pull it back. This action is crucial because it helps to stop the cycle of firing by disengaging the bolt. When a machine gun experiences a runaway condition, it means that the weapon continues to fire unintentionally, often due to a malfunction or a failure in the weapon's feeding or operating mechanism. By manipulating the cocking handle, you can interrupt the automatic cycle, preventing further rounds from being discharged and ensuring minimal risk to personnel and equipment.

Other actions, while they may seem plausible in different contexts, do not effectively address the immediate issue of a runaway gun. For example, dropping the weapon could lead to further injury or damage, especially if the weapon continues to fire upon impact. Turning off the safety would not help, as the safety mechanism would generally not be able to control a runaway situation once it has begun. Removing the ammunition belt is not ideal either, as the weapon may still discharge rounds until the cycling is stopped, potentially leading to uncontrolled firing. Therefore, grasping the cocking handle and pulling it back is the most effective and immediate response to bring the situation under control.