On May 16, 2025, the Trump Administration announced a settlement resolving several civil lawsuits, including between the U.S. federal government and Rare Breed Triggers, a company that sells forced reset triggers (FRTs). FRTs are aftermarket devices that "do not require the shooter to pull and then subsequently release the trigger before a second shot is fired," with some FRTs enabling a "firearm to automatically expel more than one shot by a single, continuous pull of the trigger." Certain FRTs are purchased and installed in semiautomatic rifles, including AR-15 platformed weapons, and thus are marketed as replacement triggers for AR-type firearms.
Federal law defines a "machinegun" as a firearm that has the ability to "shoot, automatically more than one shot . . . by a single function of the trigger" and "any combination of parts designed and intended, for use in converting a weapon into a machinegun." In 2022, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) issued a letter classifying some FRTs as "machineguns" because they allow "a firearm to automatically expel more than one shot with a single, continuous pull of the trigger." FRTs falling within the definition of a "machinegun" are subject to the possession, transfer, and transport restrictions of the Gun Control Act (GCA), and the registration, transfer, taxation, and possession restrictions of the National Firearms Act (NFA).
In 2023, the United States filed suit requesting injunctive relief to prevent Rare Breed Triggers from allegedly "illegally selling machinegun conversion devices they style as the FRT-15 to be installed in AR-15 type weapons." The United States filed a separate civil forfeiture action against more than a thousand seized FRTs and firearm parts. Firearm advocacy groups and FRT owners filed a subsequent lawsuit seeking to enjoin ATF's FRT classification.
In 2024, the Supreme Court in Garland v. Cargill held that a firearm equipped with a device called a "bump stock" is not a "machinegun" under the NFA. The Court explained that, while a bump stock allows for multiple rapid firing cycles, a bump stock is not a machinegun because "any subsequent shot fired after the trigger has been released and reset is the result of a separate and distinct function of the trigger," not a single pull of the trigger. The Court recognized that multiple functions of the trigger may be initiated by a single pull of the trigger provided that the shooter (1) maintains consistent forward pressure, (2) places their non-trigger hand on the rifle's grip, and (3) keeps their trigger finger stationary.
The suit challenging the ATF's FRT classification argued that because some FRTs do require a separate and distinct function of the trigger, they should not be regulated as machineguns. As a result of the May 2025 agreement ceasing the Rare Breed Triggers litigation and resolving similar cases, the current administration may not bring actions under the GCA and NFA with respect to certain FRTs.
MCDs are components that convert a semiautomatic firearm into one that repeatedly fires rounds with a single function of the trigger. One type of MCD is the Glock switch. A Glock switch can give a Glock pistol firing capacity and a firing mechanism similar to that of the Glock 18 fully automatic pistol, which can fire 20 rounds per second. This has led some to argue that a Glock switch that can allow a Glock pistol to continue firing up to 1,200 bullets per minute with a single pull of the trigger is a machinegun. MCDs are regulated as "a combination of parts" used to convert a firearm into a machinegun under the National Firearms Act, making them illegal to possess with limited exceptions.
Certain FRTs also have the capability to increase a firearm's rate of fire. In 2022, prior to the Cargill decision on bump stocks, ATF had classified some FRTs as machineguns because, according to ATF, they allowed "a firearm to automatically expel more than one shot with a single, continuous pull of the trigger." The U.S. Department of Justice issued a complaint against Rare Breed Triggers to enforce this position. In 2023, a federal district court granted the U.S. government a preliminary injunction, enjoining the company from selling certain FRTs. However, as noted above, in the 2024 Cargill decision the Supreme Court held that bump stocks are not machineguns because the devices do not enable semiautomatic firearms to fire more than one shot "by a single function of the trigger." According to the firearm advocacy groups' complaint, "An FRT resets after every round is fired and the trigger must engage in a separate function of releasing the hammer for each and every round fired."
The Trump Administration's decision to cease litigation may mean that ATF will also no longer consider certain FRTs to be machineguns.
The settlement between the U.S. government and Rare Breed Triggers and other claimants includes an agreement whereby Rare Breed Triggers will not produce or market FRTs for "any handgun" where the "magazine loads into the trigger-hand grip." Additionally, the hammer must "be released from its sear surface for every round fired" and "the trigger in an FRT-equipped firearm must reset after every round fired" to be covered by the agreement. Nonetheless, Rare Breed Triggers can sell FRTs for a variety of semiautomatic pistols where the magazine is inserted ahead of the grip, including AR- and AK-style pistols, TEC-9s, and others. The settlement agreement also does not preclude the United States from initiating an enforcement action against other FRT manufacturers, nor does it resolve other potential enforcement actions state regulators have taken or may take in the future. Congress could pass legislation clarifying the legal status of FRTs by either explicitly allowing or banning their manufacture and use.
Congress could also consider changing the definition of a machinegun to one that encompasses or specifically excludes items like FRTs and bump stocks, and does not hinge on whether a firearm fires more than one shot through the "single function of the trigger."