NEW ORLEANS, LA (March 16, 2021) ﹘ Today, Firearms Policy Coalition (FPC) filed an important brief in the case of Cargill v. Garland, et al with the Fifth Circuit Court of Appeals. The brief can be viewed at

The case involves another challenge to the ATF Final Rule banning bump stocks. The Final Rule impermissibly rewrote the definition of the term “machinegun” to include bump stock devices. The brief argues the ATF exceeded its delegated authority in promulgating the Final Rule and is not entitled to Chevron deference in the event the Court of Appeals finds the Final Rule contradicts the plain statutory definition of “machinegun.”

In 1986 Congress amended the Gun Control Act (GCA) and outlawed most machine guns while simultaneously making it illegal for those weapons to be registered. Under the GCA, the term “machinegun” is defined as “any weapon which shoots . . . automatically more than one shot, without manual reloading, by a single function of the trigger.” Prior to the promulgation of the Final Rule, the ATF issued dozens of classification letters. Every classification from 2006 to the promulgation of the Final Rule concluded bump stocks were not “machineguns.” In the wake of the Las Vegas massacre, several bills were introduced by Congress to specifically amend the GCA and prohibit bump stocks. All proposed bills failed to become law. Thereafter, the ATF, acting in response to political pressure, issued the Final Rule on December 26, 2018. The Final Rule alters the definition of “machinegun” specifically to include bump stock devices. Plaintiff Michael Cargill was forced to surrender his bump stocks to the ATF under protest pending the results of this litigation. 

The ATF has no authority to expand the scope of criminal liability created by Congress. The brief argues that allowing the ATF to promulgate a Final Rule which redefines the term “machinegun” impermissibly delegates to the agency the ability to make law, enforce law, and interpret law. This is in contravention of basic separation of powers and non-delegation principles. 

The brief argues the rule of lenity serves to cabin the reach of executive power in the criminal context and is at odds with a delegation implied from ambiguity. As such, the rule of lenity, in the criminal context, should apply before any deference to an agency’s interpretation of a statute under Chevron. The rule of lenity can be thought of as a “tie goes to the runner” type rule of statutory interpretation. As Justice Marshall put it: “[the rule of lenity] is founded on the tenderness of the law for the rights of individuals; and on the plain principle that the power of punishment is vested in the legislative, not the judicial department.” The Legislature in our system is afforded the sole authority to define crimes and ordain punishments. The sole function of the ATF is to enforce the law. The agency has the discretion to fill statutory gaps with regulations but it is not permitted to redefine statutory definitions in order to achieve a policy objective. Moreover, and perhaps more importantly, the ATF is not free to ignore the plain meaning of the law via imaginative interpretations. 

“The rule of lenity is a deeply rooted constitutional principle that ensures legislatures define criminal laws, and that the people have a fair warning of what conduct is prohibited,” said FPC’s Joseph Greenlee. “By contrast, the application of Chevron deference in the criminal context would violate several constitutional safeguards, including the separation of powers. We hope that the Fifth Circuit will apply the rule of lenity and rule in favor of Mr. Cargill.”   

Firearms Policy Coalition and its FPC Law team are the nation’s next-generation advocates for the right to keep and bear arms and adjacent issues, having recently filed many major federal Second Amendment lawsuits, including challenges to the State of Maryland’s ban on “assault weapons” (Bianchi v. Frosh), the State of Pennsylvania’s and Allegheny County’s carry restrictions (Cowey v. Mullen), Philadelphia’s Gun Permit Unit policies and practices (Fetsurka v. Outlaw), Pennsylvania’s ban on carry by adults under 21 years of age (Lara v. Evanchick), California’s Handgun Ban and “Roster” laws (Renna v. Becerra), Maryland’s carry ban (Call v. Jones), New Jersey’s carry ban (Bennett v. Davis), New York City’s carry ban (Greco v. New York City), the federal ban on the sale of handguns and handgun ammunition by federal firearm licensees (FFLs) to adults under 21 years of age (Reese v. BATFE), and others, with many more cases being prepared today. To follow these and other legal cases FPC is actively working on, visit the Legal Action section of FPC’s website or follow FPC on Instagram, Twitter, Facebook, YouTube.

Firearms Policy Coalition ( is a 501(c)4 nonprofit organization. FPC’s mission is to protect and defend constitutional rights—especially the right to keep and bear arms—advance individual liberty, and restore freedom through litigation and legal action, legislative and regulatory action, education, outreach, grassroots activism, and other programs. FPC Law is the nation’s largest public interest legal team focused on Second Amendment and adjacent fundamental rights including freedom of speech and due process, conducting litigation, research, scholarly publications, and amicus briefing, among other efforts.