Loading ...During my short military stint I learned that firing blanks required the use of a blank firing attachment (BFA) attached to the end of the muzzle. This allowed the escaping gas from a fired blank round to build enough pressure in the barrel to force the receiver mechanism back and eject the spent round and chamber the next round. An actual live round builds up enough pressure in the barrel behind the escaping projectile and initiates a blowback action that ejects and chambers. Without the BFA the gas simply escapes from the end of the barrel and creates no pressure to eject the spent round. The receiver must be cocked manually to chamber the next round. We NEVER mixed live rounds with blanks.
Maybe automatic firearms have changed a bit since I served, but I think probably not. Perhaps any current serving member of the Armed Forces could enlighten me.
Best, MadMike