National Firearms Act

The National Firearms Act of 1934, codified as I.R.C. ch. 53, imposes an excise tax on the manufacture and transfer of certain firearms, including machine guns, short-barreled rifles, short-barreled shotguns, silencers, and "any other weapons" that can be concealed on a person and discharge a shot by explosive energy. The law requires registration of these firearms through the National Firearms Registration and Transfer Record, and mandates reporting of their transport across state lines by the owner. The original Act regulated pistols and revolvers as strictly as machine guns, but they were ultimately excluded from the law before passage, while other concealable weapons were not.learn more on wikipedia