Despite a federal court vacating the Biden-era pistol brace rule, the ATF says it never stopped enforcing its underlying legal interpretation — and it’s not planning to.

A bombshell court filing submitted March 16 in a Southern District of Texas case has gun owners and Second Amendment advocates sounding the alarm: the Bureau of Alcohol, Tobacco, Firearms and Explosives has quietly admitted in federal court that it continues to enforce its interpretation that some pistol-brace-equipped firearms are unregistered short-barreled rifles (SBRs) — a federal felony carrying up to 10 years in prison — even though the rule that codified that interpretation has been universally vacated.

The Case

The filing came in State of Texas et al. v. Bureau of Alcohol, Tobacco, Firearms and Explosives, Civil Action No. 6:23-cv-00013, in response to a motion filed by Gun Owners of America (GOA) seeking an injunction to stop ATF from enforcing the legal theories that underpinned the now-dead brace rule. ATF filed its reply brief on March 16, 2026, arguing the case is moot — because the rule is gone — but simultaneously acknowledging that it is still enforcing the NFA’s and GCA’s regulation of short-barreled rifles against some brace-equipped pistols.

In the ATF’s own words from the filing:

“Plaintiffs also make much of the fact that defendants continue to enforce the NFA’s and GCA’s regulation of short-barreled rifles against some brace-equipped pistols, even though the Rule has been universally vacated. But that should come as no surprise…”

The agency went further, arguing that its continued enforcement is entirely independent of the rule itself:

“At any rate, that defendants continue to enforce certain statutory requirements and prohibitions that they have been delegated the authority and responsibility to administer is irrelevant to whether plaintiffs’ APA challenge to the now-defunct Rule is moot.”

Translation: the rule may be dead, but the ATF says it still has the statutory authority — and the intent — to prosecute Americans with braced pistols as felons.

Quick Backstory

Pistol stabilizing braces were developed in 2012 and initially approved by the ATF, which said attaching one to a pistol did not reclassify the firearm as a short-barreled rifle. In 2014, the agency doubled down, confirming that even shouldering a braced pistol didn’t change its classification. That reassurance helped drive adoption to an estimated 7 to 10 million or more Americans.

Things got complicated in 2015 when ATF reversed course, briefly suggesting shouldering a brace could make a gun owner a felon, before reversing that reversal in 2017. Then, in January 2023, the Biden administration dropped the hammer with a sweeping administrative rule that effectively classified the vast majority of braced pistols as unregistered SBRs. Owners were given the option to register their firearms for free — but compliance estimates ranged from only 6% to 8%.

Lawsuits flew immediately. In 2025, a federal court universally vacated the rule, and the Trump administration jointly dismissed at least one related case — Mock v. Bond — with the Firearms Policy Coalition. It seemed like the fight was over.

It wasn’t.

The Legal Catch

GOA’s lawsuit, filed in Texas, had specifically challenged the rulemaking process under the Administrative Procedure Act (APA). The ATF is now using that narrow framing against gun owners, arguing that because GOA’s lawsuit targeted the rule — not the underlying statutory interpretation — and the rule is now dead, the case is moot. The court, ATF argues, cannot enjoin the agency from enforcing legal theories that exist independent of any specific rule.

In short: you killed the rule, not our interpretation. And we’re still acting on it.

What This Means for Gun Owners

If the ATF’s position holds, millions of Americans who purchased braced pistols in good faith — relying on multiple written ATF assurances going back over a decade — could still face federal prosecution. The agency is essentially claiming that its prior written approvals don’t bind it, the rule being vacated doesn’t bind it, and that absent a court order specifically targeting its statutory interpretation, it will continue treating certain braced pistols as felony SBRs.

GOA and other Second Amendment organizations are expected to push back. But for now, gun owners holding braced pistols would be wise to consult an attorney and stay closely tuned to further developments in this case.