Which of the following is NOT one of the eight steps in the functioning of the M4 rifle?

The functioning of the M4 rifle involves a series of specific mechanical operations that take place when the rifle is fired. These operations are known as the eight steps of operation, which include chambering, feeding, locking, firing, unlocking, extracting, ejecting, and cocking. Each step is integral to the cycle of loading and firing ammunition.

Cleaning, while essential for the maintenance and proper functioning of the M4 rifle, is not considered one of the operational steps involved in the firing process. Maintenance procedures such as cleaning serve to ensure reliability and longevity of the weapon but do not occur as part of the firing cycle itself. Therefore, it stands apart from the specific steps that describe how the rifle operates during its intended use.