Small Entity Compliance Guide

Bump-Stock-Type-Devices Final Rule

27 CFR Chapter II, Subchapter B
Part 447- Importation of Arms, Ammunition and Implements of War
Part 478- Commerce in Firearms and Ammunition
Part 479- Machine Guns, Destructive Devices, and Certain Other Firearms

The Basics

The Department of Justice has issued a final rule that amends the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) regulations regarding the definition of machinegun. Specifically, the final rule amends the regulatory text of “machine gun” in Parts 447, 478, and 479 of title 27 Code of Federal Regulations (CFR) by adding the following language: “The term ‘machinegun’ includes bump-stock-type devices, i.e., a device that allows a semi-automatic firearm to shoot more than one shot with a single pull of the trigger by harnessing the recoil energy of the semi-automatic firearm to which it is affixed so that the trigger resets and continues firing without additional physical manipulation of the trigger by the shooter.” Furthermore, the final rule defines “automatically” and “single function of the trigger” as those terms are used in the statutory definition of machinegun. Specifically, “automatically” means functioning as a result of a self-acting or self-regulating mechanism that allows the firing of multiple rounds through the single function of the trigger; and “single function of the trigger” means a single pull of the trigger and analogous motions.

Because the final rule clarifies that bump-stock-type devices are machineguns, the devices fall within the purview of the NFA and are subject to the restrictions of 18 U.S.C. § 922(o). As a result, persons in possession of bump-stock-type devices must divest themselves of their devices before the effective date of the final rule by destroying the device or abandoning it at the nearest ATF office. Small entities with an inventory of bump-stock-type devices are also required to comply with the regulation.

How to Find this Rule

The Bump-Stock-Type Devices final rule is available for review in the Rules and Regulations publications library and on the Federal Register website: The amendments made by this rule appear in 27 CFR Parts 447, 478, and 479. A copy of the rule is also available on our online rulemaking docket. Simply search for “1140-AA52” at

Frequently Asked Questions

Am I covered by this rule?

In addition to individuals in possession of bump-stock-type devices, this rule affects manufacturers of bump-stock-type devices, FFLs that sell bump-stock-type devices, and other small retailers of firearm accessories that maintain an inventory of any such devices.

When does the rule become effective?

This rule will go into effect March 26, 2019; 90 days from the publication date in the Federal Register.

How should a small entity in possession of bump-stock-type devices comply with the rule?

For destruction, regardless of manufacturer or model, a bump-stock-type device must be made incapable of being readily restored to its intended function. Acceptable methods of destruction include completely melting, shredding, or crushing the device. If the device is made of metal, an alternative acceptable method of destruction is using an oxy/acetylene torch to make three angled cuts that completely severs design features critical to the functionality of the bump-stock-type device. Each cut should remove at least ¼ inch of metal per cut. Any method of destruction must render the device so that it is not readily restorable to a firing condition or is otherwise reduced to scrap.

The following diagrams serve as guidance for how to destroy certain models of bump-stock-type devices by cutting certain areas (indicated by the red lines) that are critical design features. This guidance is also available at

Download PDF with all diagrams

Additionally, as a majority of bump-stock-type devices are made of plastic material, individuals may use a hammer to break them apart so that the device is not readily restorable to a firing condition or is otherwise reduced to scrap, and throw the pieces away. Small entities are encouraged to undertake destruction of the devices. However, they also have the option to abandon bump-stock-type devices at the nearest ATF office. For assistance with identifying the closest ATF office, visit

May a firearms manufacturer, who is licensed to manufacture machineguns, manufacture bump-stock-type devices after the effective date of the regulation?

If a firearms manufacturer, who is licensed to manufacture machineguns, intends to manufacture bump-stock-type devices after the effective date of this regulation, the manufacture, subsequent transfer, and possession of such devices must comply with 27 CFR 479.105 and ATF Ruling 2014-1. For questions, please contact National Firearms Act (NFA) Division at (304) 616-4500 or

Last Reviewed December 26, 2018