ATF Rulings 2024-2026: Pistol Braces, Bump Stocks, Frames & Receivers

Bump stocks: Garland v. Cargill (June 2024)

The ATF reclassified bump stocks as "machine guns" under the National Firearms Act in 2018, making existing owners felons unless they destroyed or surrendered the devices. The reclassification followed the October 2017 Las Vegas shooting and was driven by executive-branch action, not new legislation.

Michael Cargill, a Texas firearms dealer, surrendered his bump stocks under protest and sued, arguing the ATF lacked statutory authority to redefine the term "machine gun" to include devices that didn't convert a rifle to fully automatic within the meaning of 26 U.S.C. §5845(b).

On June 14, 2024, the Supreme Court ruled 6-3 in Cargill's favor. Writing for the majority, Justice Thomas held that a semi-automatic rifle equipped with a bump stock does not fire "by a single function of the trigger" because each shot still requires the trigger to reset and be pressed again — even if the rifle's reciprocating motion does most of the work. The ATF's 2018 rule was invalidated.

Status: Bump stocks are once again legal accessories under federal law. State law varies: California, Delaware, Florida, Hawaii, Maryland, Massachusetts, New Jersey, New York, Rhode Island, Vermont, Washington, and the District of Columbia prohibit bump stocks by state statute, and those prohibitions survived Cargill.

Ghost guns: Bondi v. VanDerStok (March 2025)

In 2022, the ATF issued Final Rule 2021R-05F, redefining the term "firearm" in the Gun Control Act to include partially-machined frames and receivers that could be "readily" completed into functional firearms — the category commonly called 80% receivers or "ghost gun kits." The rule required commercial kits to bear serial numbers and move through FFL channels with 4473 and NICS, just like complete firearms.

Jennifer VanDerStok and others challenged the rule, arguing the ATF had exceeded its statutory authority by regulating components that weren't yet firearms. The Fifth Circuit struck the rule down. The Supreme Court granted cert, and on March 26, 2025, reversed: the ATF's rule was a valid exercise of agency authority under the GCA, because the statute's definition of "firearm" includes items "designed to" or "may readily be converted to" fire a projectile.

Status: The 2022 rule is in full force. Commercial 80% kits must ship through FFLs with serials and 4473. Personal manufacture of a firearm by an individual for personal use remains lawful under federal law — but the individual must serialize it per state law where required (California, New York, New Jersey, Washington, Oregon, Illinois, Hawaii, Colorado, Rhode Island, Nevada, Delaware, Maryland, Connecticut, DC all have PMF registration or serialization laws).

Pistol braces: Mock v. Garland and the aftermath

Pistol braces — originally designed as stabilizing devices for veterans with disabilities — became a popular accessory on AR-pistols and similar firearms through the 2010s. In January 2023, the ATF published Final Rule 2021R-08F, reclassifying braced pistols that met certain criteria as short-barreled rifles (SBRs) — NFA-regulated items requiring a $200 tax stamp and ATF registration.

Rather than confiscate millions of braced pistols, the ATF opened a 120-day tax-free amnesty registration period. Owners could register their firearms as SBRs under Form 1 without paying the $200 tax, destroy them, remove the brace, or install a 16"+ barrel.

Legal challenges were immediate. In Mock v. Garland, the Fifth Circuit held that the final rule differed so substantially from its noticed proposal that it violated the Administrative Procedure Act. District courts broadly enjoined enforcement. Through 2024 and into 2025, the rule was effectively stayed in most of the country.

As of the current enforcement posture in early 2026, the ATF has indicated it will not enforce the 2023 pistol brace reclassification against ordinary owners. Braced pistols manufactured and sold before January 2023 are in a practical safe harbor. However, the legal status of manufacturers' newer braced pistol designs remains contested in ongoing litigation, and several states impose independent SBR-style restrictions on braced pistols regardless of the federal position.

Status: The 2023 rule is effectively non-enforced federally. Do not assume the pre-2023 status quo has been codified — future administrations may revive enforcement. For current possession, most owners are on firm ground; for new builds, consult counsel in your state.

"Engaged in the business" rule (2024)

The Bipartisan Safer Communities Act of 2022 amended the definition of "engaged in the business" of dealing firearms — the line between a private collector who occasionally sells and a person who needs an FFL. In April 2024, the ATF published Final Rule 2022R-17F implementing the statutory change.

The new definition lowers the threshold: anyone who repetitively sells firearms for profit is presumed to be engaged in the business and therefore required to be licensed. The rule eliminates the old "principal objective of livelihood" standard and replaces it with a "predominant intent to earn a profit" test.

Practical effect: many previously-unlicensed private sellers at gun shows and online platforms now need an FFL or risk prosecution for unlicensed dealing. The rule expanded background check coverage at gun shows by closing what critics called the "gun show loophole" at the federal regulatory level.

Status: The rule is in effect. Challenges are pending in multiple circuits. The ATF has issued additional guidance documents. Any private seller conducting frequent transactions should either get an FFL, stop the transactions, or seek counsel.

Forced-reset triggers

Forced-reset triggers (FRTs) and similar binary/positive-reset devices allow semi-automatic rifles to fire at rates approaching full-auto, using a mechanism that resets the trigger automatically after each shot. In 2021–2022, the ATF classified certain FRTs as machine guns under the NFA, citing the Akins Accelerator line of precedent.

Litigation has been fragmented. In National Association for Gun Rights v. Garland, a district court rejected the ATF classification as to certain FRT models. Other courts have sustained ATF classifications for other models. The Fifth Circuit and the Supreme Court have not yet resolved the question cleanly.

Status: Unsettled. Ownership of devices sold as FRTs is high-legal-risk. ATF enforcement actions against sellers and possessors have continued. Do not assume a device is lawful based on its retail labeling — request model-specific counsel in your jurisdiction.

What it means for buyers and FFLs

For buyers

• Bump stocks: legal federally, check state law before purchase. Cargill doesn't preempt state bans.
• 80% kits: commercial kits now require FFL transfer. Personal manufacture (without commercial sale) remains lawful federally but check state registration laws.
• Braced pistols: ordinary possession broadly safe; new builds carry residual legal risk until the landscape fully settles.
• Gun show / online private sales: the "engaged in the business" threshold has dropped. Selling more than a handful of firearms for profit per year likely requires an FFL.

For FFLs

• More transfers in the pipeline. 80% kits and formerly-private sales now funneling through licensed dealers means more volume — and more liability for correct 4473 handling.
• Expanded compliance surface. The engaged-in-business rule means FFLs may see applications from prior hobbyist sellers. The C&R collector segment is distinct and unaffected.
• Pistol brace guidance: stock or remove braces based on the individual state posture. Don't rely on a single national answer.