BUMP Act
- Sponsor
- Sen. Heinrich, Martin [D-NM]
- Committees
- Judiciary Committee (primary)
- Last action
- Apr 9, 2025
Bottom line
The BUMP Act expands federal firearm regulations to ban devices and modifications that enable semiautomatic firearms to fire at machinegun rates, requiring registration for pre-existing modified weapons.
What it actually does
This bill amends federal law to prohibit the import, sale, manufacture, transfer, receipt, or possession of devices designed to materially increase the rate of fire of a semiautomatic firearm or approximate the action of a machinegun. It also prohibits semiautomatic firearms modified in such a way and requires existing modified firearms to be registered under the National Firearms Act.
Proponents argue
Supporters argue this bill closes a dangerous loophole that allows accessories like bump stocks to effectively convert legal semiautomatic firearms into illegal machineguns, thereby enhancing public safety and reducing gun violence. They emphasize that it targets specific accessories and modifications, not firearms themselves, aiming to prevent mass casualty events.
Opponents contend
Opponents may argue that the bill infringes on Second Amendment rights by restricting accessories that are not themselves firearms and that the definitions could be overly broad, potentially criminalizing common firearm parts or modifications. They might also contend that existing laws are sufficient or that such measures do not deter criminals.
The bill is very short and its core provisions are easily digestible, allowing for a quick and thorough understanding of its intent and scope.
Section 2(a)(1), amending 18 U.S.C. 921(a)
Definition of Semiautomatic Firearm
This provision adds a new definition for 'semiautomatic firearm' to federal law. It defines such a firearm as one that fires a cartridge, uses energy from firing to extract and chamber the next round, and prepares the firing mechanism, but crucially, requires a separate trigger pull for each shot and is not classified as a machinegun.
Supporters argue
Supporters would argue that a clear, statutory definition of 'semiautomatic firearm' is essential for the precise application and enforcement of the subsequent prohibitions, preventing ambiguity in the law.
Critics contend
Opponents might argue that defining 'semiautomatic firearm' in this manner could be a precursor to broader restrictions on these types of firearms, even if this specific bill only targets modifications.
Tradeoffs
The tension lies between providing clarity for enforcement and potentially setting a precedent for future legislative actions concerning semiautomatic firearms.
Section 2(a)(2), inserting 18 U.S.C. 922(v)(1)
Prohibition on Devices and Modifications Increasing Rate of Fire
This section makes it unlawful to import, sell, manufacture, transfer, receive, or possess any manual, power-driven, or electronic device primarily designed to materially increase a semiautomatic firearm's rate of fire or approximate a machinegun's action. It also prohibits any device, part, or combination of parts that eliminates the need for a separate trigger movement for each shot, and any semiautomatic firearm modified in such a way. This prohibition takes effect 120 days after enactment.
Section 2(a)(2), inserting 18 U.S.C. 922(v)(2)
Registration of Pre-Existing Modified Semiautomatic Firearms
Individuals who lawfully own or possess a semiautomatic firearm that was modified as described in the prohibition *before* the date of enactment must register that firearm with the federal government within 120 days of enactment. This registration must be done in accordance with section 5841 of the Internal Revenue Code of 1986, which governs items under the National Firearms Act.
Section 2(a)(2), inserting 18 U.S.C. 922(v)(3)
Government Exceptions
The prohibitions and registration requirements established by this bill do not apply to the importation, manufacture, sale, transfer, or possession by or under the authority of the United States government, any department or agency thereof, or a State or Tribe, or a department, agency, or political subdivision thereof.
Section 2(a)(2), inserting 18 U.S.C. 922(v)(4)
Exception for Lawfully Modified and Registered Firearms
The general prohibition on devices and modified firearms does not apply to any lawful transfer or possession of a semiautomatic firearm that was lawfully modified and possessed before the enactment date, *provided* it is registered in accordance with the new registration requirement outlined in paragraph (2).
Section 2(b), amending 26 U.S.C. 5845(a)
Inclusion of Modified Semiautomatic Firearms under National Firearms Act
This amendment explicitly adds semiautomatic firearms modified to materially increase their rate of fire or approximate machinegun action (as defined in the new 18 U.S.C. 922(v)(1)(C)) to the list of items regulated under the National Firearms Act (NFA). This subjects these firearms to the stringent NFA requirements, including taxation, registration, and transfer restrictions.
Amends the National Firearms Act (NFA) to include semiautomatic firearms modified to increase their rate of fire or approximate machinegun action as NFA items.
Section 2(b)
Why it matters:While amending existing statutes is standard legislative practice, the substantial impact of classifying a new category of items under the NFA could be easily missed by those unfamiliar with the intricacies of firearms law.
Case for: Supporters argue this ensures the most dangerous modifications are regulated with the same strictness as other NFA items, requiring extensive background checks, registration, and taxation, thereby enhancing public safety.
Case against: Opponents contend that classifying modified semiautomatics as NFA items is an overreach, subjecting common firearms to regulations intended for inherently dangerous weapons, potentially leading to confiscation or severe penalties for non-compliance.
Estimated impact: Significantly increases the regulatory burden and potential criminal penalties for owners of affected firearms, subjecting them to a $200 tax stamp and federal registration.
These phrases define the threshold for what constitutes a prohibited device or modification, focusing on whether it 'materially increases the rate of fire' or 'approximates the action or rate of fire of a machinegun.'
Section 2(a)(2), inserting 18 U.S.C. 922(v)(1)(A) and (C)
Why it matters:This is standard legislative drafting to define the scope of a prohibition. However, the inherent subjectivity of terms like 'materially increases' and 'approximates' can lead to significant real-world consequences depending on regulatory interpretation.
Case for: Proponents argue this language provides necessary flexibility for regulators to address new technologies and modifications that emerge, ensuring the spirit of the law is maintained even as designs evolve and preventing easy circumvention.
Case against: Critics argue this language is vague and could lead to arbitrary enforcement, potentially criminalizing accessories or modifications that were not explicitly intended to be prohibited, creating legal uncertainty for firearm owners and manufacturers.
Estimated impact: The interpretation of these phrases will determine the precise scope of the prohibition, affecting potentially thousands of firearm accessories and modifications, and shaping future enforcement actions by the ATF.