What do the initials PDF stand for in machine gun terminology?

The initials PDF stand for "Final Defensive Fire" in machine gun terminology. This term describes a critical phase in which the machine gun is employed in a defensive role to protect a position or unit from an imminent threat. It is typically used as a last line of defense against an attacking force.

Final Defensive Fire involves the machine gun directing suppressive fire toward enemy forces that are closing in on friendly positions. The emphasis during this phase is on delivering effective and concentrated fire to halt the advance of the enemy and provide support to troops who may be engaged in close-quarters combat. Understanding the concept of Final Defensive Fire is vital for ensuring that tactics are effectively employed during high-pressure scenarios where the survival of a unit may depend on the rapid and lethal response of machine gunners.

The other terms, while they may sound plausible, refer to different concepts or strategies that do not capture the essence of what PDF means in this context.