Unlocking and eradicating the expended case in the chamber and ejecting it out of the weapon as bolt is shifting rearward Equally barrel and breechblock, locked with each other, recoiled a short distance on the rear; then the barrel was stopped as well as the block continued back alone. https://beltfedmachinegun73625.weblogco.com/38519815/a-simple-key-for-m4-unveiled