When executing STACK ARMS, what part of the rifle is grasped with the left hand?

When executing STACK ARMS, the proper technique involves grasping the Hand Guards of the rifle with the left hand. This ensures a secure grip while allowing the right hand to facilitate the stacking action, which is crucial for maintaining the integrity and control of the weapon during this maneuver. The Hand Guards provide a comfortable and stable section of the rifle to hold, and they also allow the individual to properly align the rifle with others in a stack, which is essential for safety and organization within a formation.

Additionally, the Hand Guards offer a balance point that helps in maintaining control while executing the movement, as it is important not to grip areas of the rifle that could lead to an unsafe or unstable position, such as the Barrel or Stock. This technique is a fundamental aspect of drill and ceremony, emphasizing precision and discipline in Marine Corps practices.