What is a common characteristic of a machine gun's firing mechanism?

The firing mechanism of a machine gun is specifically designed for automatic or sustained fire, which is a fundamental characteristic that distinguishes it from other firearm types. This capability allows a machine gun to fire a continuous stream of ammunition as long as the trigger is held down, making it effective for laying down suppressive fire or engaging multiple targets in rapid succession. This automatic firing feature is crucial for military and tactical operations where a high rate of fire is necessary to achieve combat objectives.

In contrast, options that suggest semi-automatic modes, manual cycling after each shot, or the limitation to single shots describe mechanisms associated with different types of firearms, such as rifles or pistols, and do not apply to the operation of machine guns. The focus of machine guns on automatic fire is essential for understanding their role in combat scenarios.