Strangest, hard to explain thing I ever saw was my 1SG wanted to demonstrate the potential of injury with a M200 blank round from a M16A1. Without the blank adaptor on the muzzle, he attempted to demonstrate the damage which can be done to a styrofoam coffee cup placed over the muzzle when firing the blank round. With the rifle on safe, he loaded a magazine, yanked the charging handle, dropping the bolt with the muzzle down and it fired the blank round. The rifle did not feed or chamber the next round from the magazine, nor did it eject the fired one.
I saw the selector was on safe.
He then charged the rifle with the muzzle elevated, he placed cup on muzzle, rolled the selector to fire and let it rip. Cup was quite damaged. Point well received by the troops, but he and I stepped aside and took a peek at the rifle and brass.
When I was in tech school in the AF the instructors said they used blanks to kill snakes (less the blank adapter of course.). Without the blank adapter all the gas goes out the muzzle. Not enough or none goes into the gas tube which cycles the action. This is why the rifle did not feed another round.
