In 1982, I witnessed a fellow have a misfire, instantly drop the butt to the ground, and put his mouth over the barrel. All of us screamed at him, mostly out of horror about the consequences. The rifle did not go off, but it was loaded, and had sustained a bust cap without the charge going off. I'll never forget the dumb look on his face. Placing any body part over the muzzle of a rifle/gun, apart from the loading process, is not a good practice to get into, to the point of it becoming a habit. Just my opinion.