What is a key feature of the M320?

The M320 is an important weapon system used by infantry units, particularly due to its versatility in handling various types of ammunition. One of its key features is that it can be fired in double-action mode. This means that the shooter can pull the trigger to both cock the hammer and fire the round, which can enhance the speed of firing in certain situations. This capability is significant for tactical operations requiring quick responses to threats without the need to manually cock the weapon.

The M320's design allows for greater flexibility in how it is employed in the field. It can accommodate various ammunition types, thus providing soldiers with different options based on the mission requirements. This adaptability makes the M320 a valuable asset in combat scenarios.

In contrast, other features mentioned in the options do not accurately describe the M320. It does not utilize a magazine feeding system as traditional rifles do, nor is it capable of automatic firing. Furthermore, while it is advantageous for a weapon to have a collapsible stock, the primary focus here should be on the mechanism of operation, which distinctly highlights the feature of being able to operate in double action.