In sequence, which is the first step in the cycle of operations of the M16A2 service rifle?

The correct answer, firing, represents the critical first action within the cycle of operations of the M16A2 service rifle. Once a round is chambered and the shooter pulls the trigger, the firing pin strikes the primer, igniting the propellant and causing the bullet to exit the barrel. This initiation of the firing process is fundamental as it sets off the subsequent phases of the cycle, which include extraction, ejection, and reloading. Understanding this sequence is vital for effective usage and maintenance of the rifle, as each step depends on the successful execution of firing to continue the cycle. This foundational knowledge supports Marines in ensuring their weapon functions reliably and effectively in various operational contexts.