What action is taken when the gunner loses sight of the Assistant Gunner in defilade?

When the gunner loses sight of the Assistant Gunner while in defilade, calling out "Mark!" allows the gunner to record the distance to the last known position of the target. This communication technique is crucial in maintaining situational awareness and ensuring that both the gunner and the Assistant Gunner can effectively coordinate their actions even when visibility is compromised.

By marking the distance, the gunner can refer back to this information to adjust fire if necessary or to prepare for potential subsequent engagements. This action emphasizes the importance of communication and maintaining tactical efficiency in a dynamic operational environment. It helps ensure that the team can act cohesively, particularly when visual contact is lost due to obstacles or terrain features that obscure sight lines.