The Trump Administration has proposed a new rule that would ban bump stocks, devices that are used to make semiautomatic guns operate like machine guns. The shooter in the Las Vegas shooting used a bump stock. Bump stocks are banned in some States, including Delaware, Hawaii, and Florida.

In December of 2018, the Department of Justice wrote that it was

“… amending the regulations of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) to clarify that bump-stock-type devices—meaning “bump fire” stocks, slide-fire devices, and devices with certain similar characteristics—are “machineguns” as defined by the National Firearms Act of 1934 and the Gun Control Act of 1968 … Specifically, these devices convert an otherwise semiautomatic firearm into a machinegun by functioning as a self-acting or self-regulating mechanism that harnesses the recoil energy of the semiautomatic firearm in a manner that allows the trigger to reset and continue firing without additional physical manipulation of the trigger by the shooter. Hence, a semiautomatic firearm to which a bump-stock-type device is attached is able to produce automatic fire with a single pull of the trigger. With limited exceptions, the Gun Control Act, as amended, makes it unlawful for any person to transfer or possess a machinegun unless it was lawfully possessed prior to the effective date of the statute. The bump-stock-type devices covered by this final rule were not in existence prior to the effective date of the statute, and therefore will be prohibited when this rule becomes effective. Consequently, under the final rule, current possessors of these devices will be required to destroy the devices or abandon them at an ATF office prior to the effective date of the rule.”

Democratic lawmakers like Senator Dianne Feinstein (CA-D) believe that this is not enough to stop mass shootings. She wrote in a Washington Post editorial:

Only hours after the Trump Administration released its final regulation, Gun Owners of America announced it would file a lawsuit.To ensure a ban is implemented and protected from legal challenges, Congress must still pass a law banning bump stocks and other similar devices, such as trigger cranks.

For more background, see the March 2013 issue of Congressional Digest on “Gun Violence Prevention,” the November 1999 issue of Congressional Digest on “Firearms in America,” the April 2010 issue of Supreme Court Debates on “Gun Control in the States,” and the May 2008 issue of Supreme Court Debates on “The Second Amendment.”