Which principle allows the machine gun to fire without being exposed to enemy observation or fire?

The principle that allows the machine gun to fire without being exposed to enemy observation or fire is defilade. Defilade refers to positioning a weapon in a manner that hides it from direct enemy sight and fire, typically utilizing terrain features like hills, embankments, or depressions. By using defilade, a machine gunner can employ the weapon effectively while minimizing the risk of being targeted or detected by the enemy.

This principle is crucial for maintaining the element of surprise and enhancing survivability on the battlefield. When a machine gun is set in a defilade position, it can provide suppressive fire or support to troops without compromising its own security. This method allows for effective engagement of targets while maintaining a strategic advantage over the enemy.

In contrast, while concepts like economy of fire, cover and concealment, and mutual support are all important in a combat scenario for different reasons, they do not specifically address the need to fire without visibility or exposure to enemy forces in the same way that defilade does.