ATF Revises Machine Gun Definition Following Supreme Court Ruling

The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is amending federal regulations concerning the definition of a “machine gun” in response to a recent Supreme Court decision. This rule change effectively removes bump-stock-type devices from the federal definition of a machine gun, aligning ATF regulations with the Court’s ruling. The changes will take effect on May 6, 2026.

The Supreme Court’s decision in Garland v. Cargill determined that the ATF had exceeded its statutory authority with a 2018 rule that classified bump stocks as machine guns. The Court found that a semi-automatic rifle equipped with a non-mechanical bump stock does not meet the statutory definition of a machine gun, which requires a weapon to fire more than one shot “by a single function of the trigger” and to do so “automatically.” Consequently, the ATF is removing the specific language from its regulations that incorporated bump stocks into the definition of a machine gun.

These regulatory updates will restore the definitions of “machine gun” in parts 447, 478, and 479 of the Code of Federal Regulations to their pre-2018 status, with a minor technical amendment to punctuation in one section. The ATF is making these changes to ensure its regulations are consistent with the Supreme Court’s interpretation of federal firearms laws, thereby preventing public confusion. The agency has determined that public notice and comment are unnecessary for this rule, as it is a direct response to the Court’s mandate. The rule is being made effective immediately upon publication due to a finding of good cause, as delaying the effective date would not serve the public interest.

The ATF estimates that this regulatory change will result in significant quantifiable benefits. By rescinding the 2018 rule’s provisions, the agency projects a substantial increase in the potential production and sales of bump stocks. Using historical data and accounting for inflation, the ATF estimates an average retail value of 330 per bump stock. With an estimated future production rate of 62,084 units annually, the agency calculates an annualized benefit of at least 20,487,720, or over $204 million within a decade. Additionally, individuals who surrendered bump stocks following the 2018 rule will have the opportunity to retrieve their property, representing a qualitative benefit. The rule is also expected to provide consumers with greater options for accessorizing and modifying their firearms.

The ATF has determined that this rule imposes no new costs. It is considered a deregulatory action as it removes restrictions on the sale and purchase of bump stocks. The agency has also confirmed that the rule does not involve any new information collection requirements or create criminal regulatory offenses, thus exempting it from certain Executive Order requirements. Furthermore, the rule is not expected to have substantial direct effects on state governments and does not impose significant costs on small entities, local governments, or the private sector.

Article by Mel Anara, based upon information from the Bureau of Alcohol, Tobacco, Firearms and Explosives

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