Marine Corps Knowledge Practice 2025 - Free Marine Corps Practice Questions and Study Guide

The M16A2 is designed with specific operational features, one of which is its air-cooled mechanism. This characteristic allows the barrel to cool down through the natural flow of air when the weapon is fired, which is essential during prolonged engagements. The gas-operated system facilitates reliable cycling of the action, drawing energy from the expanding gases of the fired cartridge to eject the spent casing and chamber a new round.

In contrast, the M16A2 is not water-cooled, as that would require a more complex and heavier system to manage coolant and significantly alter the weapon's portability and rapid-fire capabilities. Water-cooled firearms are typically used in heavy machine guns or other applications where sustained fire may lead to overheating, which is not a standard operational need for the M16A2 during typical engagements. Additionally, being shoulder-fired means that it is designed to be operated from the shoulder, promoting stability and accuracy during fire. Thus, the identification of "water-cooled" as a non-characteristic of the M16A2 highlights its design focus on efficiency, simplicity, and portability for infantry use.