BAMC Promotion Board Practice Exam

Eight cycles. The M4’s cycle of function is the eight sequential actions the rifle performs each time a shot is fired: feeding a round from the magazine, chambering it, locking the bolt, firing the round, unlocking the bolt, extracting the spent case, ejecting the case, and resetting the action to begin the next cycle. After the shot, the gas system drives the bolt carrier rearward, completing unlocking, extraction, and ejection; as the bolt returns forward, it strips the next round from the magazine and chambers it, re-establishing the lock for the next fire. This sequence repeats with each trigger pull.