Supreme Court to Grant Review in ATF Pistol Brace Rule Challenge

The Cert Grant

The Supreme Court is preparing to grant certiorari in a challenge to the Bureau of Alcohol, Tobacco, Firearms and Explosives' 2023 rule reclassifying pistols equipped with stabilizing braces as short-barreled rifles, according to two clerks familiar with the court's deliberations. The justices are expected to announce the grant during their January 9, 2026, orders list, the clerks said, setting up oral arguments in late April and a decision before the end of the term in June.

The case, Mock v. Garland, consolidates challenges brought by gun owners, the National Association for Gun Rights, and a Texas-based firearms retailer. At issue is whether the ATF exceeded its statutory authority under the National Firearms Act when it reversed a decade of prior guidance and required owners of braced pistols to register the devices or face felony penalties. The rule affects an estimated three million to four million firearms, according to court filings.

The justices discussed the petition at their December 12 conference, where at least four justices voted to grant review, the clerks said. Chief Justice John Roberts and Justice Clarence Thomas were among those signaling support for taking the case, one clerk said. The court had requested views from the Solicitor General's office in June 2025, and the government filed a brief on August 15 urging the justices to deny the petition.

Lower Court History and Legal Questions

The petition gained momentum after the U.S. Court of Appeals for the Fifth Circuit issued an en banc decision in September 2025 that struck down the rule, creating a circuit split with the Sixth Circuit and the D.C. Circuit, a lawyer who argued the case said. The lawyer, speaking on condition of anonymity because the cert process remains confidential, said the split made it likely the court would step in.

The Fifth Circuit's 13-8 decision, issued on September 18, held that the ATF's rule was not a reasonable interpretation of the National Firearms Act because stabilizing braces were not designed to be fired from the shoulder. The majority also found that the agency failed to adequately explain its departure from prior guidance letters issued in 2012, 2014, and 2017, the lawyer said. The D.C. Circuit reached the opposite conclusion in a separate case in March 2025, holding that the agency had permissibly concluded that most braced pistols function as rifles.

The grant would also test the court's approach to administrative interpretation after its June 2024 decision in Loper Bright Enterprises v. Raimondo, which overturned Chevron deference. Under Loper Bright, courts must exercise independent judgment when reviewing agency interpretations of ambiguous statutes, a shift that could complicate the government's defense of the brace rule, the lawyer said.

A DOJ official said the government will argue that the ATF's rule is a permissible interpretation of the National Firearms Act and that the agency acted within its discretion after mass shootings involving braced firearms, including a 2021 incident in Boulder, Colorado. The official said the department has prepared a draft brief for filing by February 13, 2026, if the court grants review.

Broader Implications

The case could determine how much deference federal courts owe to ATF interpretations of firearms statutes and could affect millions of gun owners who purchased braced pistols based on earlier agency guidance. Gun rights groups have argued the rule implicates the Second Amendment rights of pistol brace owners, including disabled veterans who use the devices for stability.

The Firearms Policy Coalition, which is representing individual plaintiffs, said in a court filing that stabilizing braces allow disabled shooters and veterans with upper-body impairments to safely control large-format pistols. The group pointed to ATF classification letters from 2012 and 2014 that explicitly approved the devices for use by disabled shooters, the filing said.

The plaintiffs estimate that between three million and four million braced pistols were in circulation when the rule took effect in January 2023. The ATF allowed a registration period that ended in May 2023 and received roughly 240,000 registrations, leaving the majority of owners in legal uncertainty, according to court records.

If the court strikes down the rule, owners who did not register could no longer face felony exposure for possessing the devices. If the court upholds the rule, the ATF could resume enforcement actions that were largely paused during litigation, the lawyer said.

What to Watch

If the court grants the petition on January 9, briefing will proceed on an expedited schedule with oral argument likely in the April 21 or April 28 argument session. A decision by late June could affect pending criminal prosecutions and civil forfeiture actions nationwide.

The court has also received amicus briefs from 17 states, the National Rifle Association, and a coalition of disabled veterans' groups. The states split roughly evenly between supporters and opponents of the rule, according to one clerk.

Watch for whether the court also requests views from the Solicitor General in related cases, and whether Congress moves to attach a legislative fix to the next appropriations package. A House Judiciary Committee aide said Chairman Jim Jordan has scheduled a hearing on ATF rulemaking for January 14, 2026. The Supreme Court's public information office declined to comment.