The Supreme Court’s ghost guns ruling, issued 7–2 on March 26, 2025, in Bondi v. VanDerStok, upheld the ATF’s 2022 rule that treats weapon parts kits and unfinished frames as firearms under the Gun Control Act of 1968.1Justia U.S. Supreme Court. Bondi v. VanDerStok, 604 U.S. ___ (2025) In practical terms, kits and near-complete frames now have to carry serial numbers, and buyers have to pass a background check before taking one home.
What the Court Decided
Justice Gorsuch, writing for the majority, held that the ATF rule is “not facially inconsistent” with the Gun Control Act.1Justia U.S. Supreme Court. Bondi v. VanDerStok, 604 U.S. ___ (2025) The statute defines a “firearm” to include any weapon that “may readily be converted” to fire a projectile, and it separately covers the “frame or receiver” of any such weapon.2Office of the Law Revision Counsel. 18 U.S.C. 921 – Definitions
The majority reasoned that “weapon” is defined by what a thing is made to do, not by whether it is finished. Congress made that clear by including “starter guns” in the statute: a starter gun cannot fire a real projectile as sold, yet the law calls it a weapon. Because converting a starter gun to a working firearm takes basic tools and under an hour, a kit like Polymer80’s “Buy Build Shoot” — which comes with every component and instructions — is at least as “readily converted.”3Supreme Court of the United States. Bondi v. VanDerStok, No. 23-852 (2025) The same logic covers near-complete frames: if an ordinary person would call the object a frame, the statute reaches it.
The Court was careful about the scope of its holding. The majority rejected only a facial challenge, meaning the argument that the rule is invalid in every possible application. Specific products could still be challenged in future cases as falling outside the rule’s reach.4Congress.gov. Supreme Court Upholds ATF Ghost Gun Regulation in Bondi v. VanDerStok
Justice Thomas dissented on the merits. He argued that Congress used the “readily converted” language in the definition of “weapon” but left it out of the definition of “frame or receiver,” and that courts normally treat such omissions as intentional. In his view, an object cannot be “not yet a receiver” and a “receiver” at the same time, and the ATF should not be able to classify items based on marketing materials and included jigs rather than the physical object itself. He also invoked the rule of lenity for ambiguous criminal statutes.3Supreme Court of the United States. Bondi v. VanDerStok, No. 23-852 (2025)
What the Rule Now Requires
ATF Final Rule 2021R-05F took effect on August 24, 2022, and the Supreme Court’s decision settles its validity.5Bureau of Alcohol, Tobacco, Firearms and Explosives. Definition of Frame or Receiver and Identification of Firearms The rule reaches two categories of product that used to slip through the definitions: partially complete frames or receivers that can be finished into a working part without specialized equipment or expertise, and weapon parts kits sold with everything needed to assemble a functioning gun.
For anyone buying one of these items from a licensed dealer, the process now looks like a standard firearm purchase. The kit or frame arrives with a serial number engraved by the manufacturer. The dealer records the sale on ATF Form 4473, which captures the buyer’s identity and the details of the item.6Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF Form 4473 – Firearms Transaction Record Revisions The buyer has to pass a NICS background check before taking possession. Dealers must keep transaction records indefinitely, replacing the previous 20-year limit.4Congress.gov. Supreme Court Upholds ATF Ghost Gun Regulation in Bondi v. VanDerStok
The rule also created the category of “privately made firearm” for any gun built by someone other than a licensed manufacturer that lacks a serial number. When a dealer takes a privately made firearm into inventory, it has to be serialized within seven days or before resale, whichever comes first.7Bureau of Alcohol, Tobacco, Firearms and Explosives. Privately Made Firearms The dealer can do the engraving in-house, send it to another licensee, or use an unlicensed engraver working under direct supervision.8Bureau of Alcohol, Tobacco, Firearms and Explosives. Summary of Final Rule 2021R-05F
Penalties for noncompliance are significant. ATF will move to revoke a dealer’s federal firearms license for willful violations such as skipping background checks, falsifying records, or transferring a firearm to a prohibited person.9Bureau of Alcohol, Tobacco, Firearms and Explosives. Revocation of Firearms Licenses Willful violations of the Gun Control Act carry up to five years in federal prison, with certain offenses reaching 10 or 15 years.10Office of the Law Revision Counsel. 18 U.S.C. 924 – Penalties
Can You Still Build a Gun for Yourself
Yes. Federal law does not prohibit individuals from building firearms for their own personal use, and the ATF rule does not change that. If you machine a receiver in your own workshop and keep the finished gun for yourself, you are not required to serialize it or run a background check on yourself, and no federal license is needed, provided you are not otherwise prohibited from possessing a firearm.
The obligations attach when a privately made firearm enters the commercial system. Bring a homemade gun to a dealer for sale, trade, or certain repairs, and the dealer has to serialize it within the seven-day window.7Bureau of Alcohol, Tobacco, Firearms and Explosives. Privately Made Firearms The rule also created a new category of dealer license for gunsmiths who want to offer serialization services to private owners.8Bureau of Alcohol, Tobacco, Firearms and Explosives. Summary of Final Rule 2021R-05F Building firearms with the intent to sell them without a federal license remains a federal crime whether or not the gun has a serial number.
Plastic and 3D-Printed Guns
The Undetectable Firearms Act of 1988 applies separately and reaches everyone, commercial sellers and home builders alike. It is illegal to manufacture, possess, or transfer a firearm that cannot be detected by a standard walk-through metal detector. The gun must be at least as detectable as a security exemplar containing 3.7 ounces of stainless steel shaped like a handgun, and the major components must produce an accurate image under standard airport screening equipment.11Office of the Law Revision Counsel. 18 U.S. Code 922 – Unlawful Acts
If you 3D-print a firearm at home, it still has to contain enough metal to trigger a detector. A fully plastic gun with no metal insert violates federal law whether you plan to sell it or keep it in a drawer.
State Laws Still Apply
About 16 states have their own ghost gun regulations that operate independently of the federal rule. Some require serialization and background checks for component parts. Others ban 3D-printed firearms outright, restrict the distribution of digital gun blueprints, or require owners to register existing unserialized guns with state authorities. A handful of states also prohibit plastic firearms that could evade metal detection, layering additional restrictions on top of the Undetectable Firearms Act.
Because these state laws come from state legislatures rather than federal rulemaking, the Supreme Court’s decision had no direct effect on them, and they often go further than what ATF requires. If you live in one of those states, you have to comply with both the federal rule and whatever your state adds on top.