Why aren’t bump fire stocks regulated like machine guns?

By Daniel Terrill

The bump stock attached to an AR rifle. (Photo: Eve Flanigan/Guns.com)
Details about bump stocks and machine guns have been making headlines across the country after the Las Vegas shooting, but what are those laws and why don’t they cover bump stocks?
The two primary laws that permit the federal government to regulate guns include the National Firearms Act and the Gun Control Act. The former was designed to create a tax on uncommon weapons while the latter permits the feds to regulate firearms in interstate commerce. The Bureau of Alcohol, Tobacco, Firearms and Explosives enforces both of them.
The NFA imposes a $200 tax on the manufacture, sale and transfer of machine guns as well as silencers, short barreled rifles or shotguns, devices deemed Any Other Weapon, and destructive devices. In addition to the tax, they require a rigmarole of paperwork and checks.
Detailing the history behind the law, the American Bar Association said Congress passed the legislation in response to Prohibition-era violence. “The act had the added incentive to curtail the use of weapons popular in gangland-style shootings, such as the St. Valentine’s Day Massacre in Chicago in 1929 when four of Al Capone’s henchmen, dressed as policemen, murdered seven members of

Source: Guns.com