A proposed rule change about arm braces on pistols prompted this correspondent to research the history of shoulder stocks, pistols, and the National Firearms Act (NFA). When the National Firearms Act of 1934 was passed, pistols with shoulder stocks were not mentioned. Short barreled rifles were not intended to be in the law. They were inserted at the insistence of a confused congressman on the House Ways and Means Committee.Fitting a pistol with a shoulder stock had always been an option. The 1934 NFA was imagined to be regulating shotguns which had been shortened to create concealable, awkward pistols, not...