The reason it jams is a failure to feed caused by subsonic rounds, allowing the slide to cycle improperly. Rookie move. Not a pro.
Lame. The heads were removed to gain access to the internal steel mounting frame. They were installed headless during original construction, and the heads affixed once securely mounted. Removing them required the opposite procedure. The muzzies frequently behead falsely accused teachers and others on the streets of Paris to send a message, not statues.