Which of the following is a guideline for handling M240 ammunition?

The guideline for handling M240 ammunition emphasizes that ammunition containers should not be opened until the ammunition is actually needed for use. This practice is essential for maintaining the integrity and safety of the ammunition. Sealed containers provide protection against environmental factors such as moisture and contaminants, which can degrade the quality of the ammunition and compromise its performance.

Keeping the ammunition sealed until it is required prevents unnecessary exposure and helps in ensuring that the ammunition remains in optimal condition, thus maximizing its reliability when used in the field. Additionally, maintaining sealed containers aids in inventory control and reduces the risk of mishandling or accidental discharge.