Which of the following is NOT a mode of operation for the M240?

The correct choice identifies "Burst" as not being a mode of operation for the M240. The M240 machine gun is primarily designed for sustained fire and operates in modes that emphasize continuous or single-shot capabilities.

The single shot mode allows for precision firing by enabling the shooter to fire one round at a time. This can be advantageous for targeting specific threats without unnecessary ammunition expenditure.

The automatic mode is characterized by the capability of the weapon to continue firing as long as the trigger is held down. This is useful for providing suppressive fire during combat scenarios, allowing the shooter to maintain a high rate of fire to suppress enemy movement.

Rapid fire refers to firing at a high rate but does not correlate to an official operational mode distinct from automatic firing in the context of the M240.

Burst mode, which typically involves the weapon firing a predetermined number of rounds with each trigger pull before automatically resetting, is not a designated operating mode for the M240. This makes "Burst" the correct answer as it does not represent how the M240 functions in the field.