Machine Gun. In an effort to curb the  violence in movies, the new "production codes" forbade the use of  the weapon by gangsters on camera for fear that it would corrupt the  youth of America (A fact explained in the "Angels With Dirty Faces"  DVD documentary). This fact is especially evident during the lodge  shoot out. All of the cops and FBI agents have Tommy Guns, 12 gauge  pump shotguns, and automatics while the gangsters only have  revolvers and lever