What Are Ghost Guns?
"Ghost gun" is a commonly used term for a privately made firearm that generally lacks a serial number applied by a licensed manufacturer. The term can refer to firearms made from unfinished frames or receivers, weapon parts kits, 3D-printed components, or other combinations of parts.
The federal government generally uses the term privately made firearm (PMF) rather than "ghost gun." ATF defines a PMF as a firearm, including a frame or receiver, completed, assembled or otherwise produced by someone other than a licensed manufacturer. ATF also makes clear that not all PMFs are illegal and that federal law does not require every firearm to have a serial number.
The legal landscape changed significantly after the Supreme Court's March 26, 2025 decision in Bondi v. VanDerStok. The Court held that the Gun Control Act covers certain weapon parts kits and that ATF's 2022 rule was consistent with the statute.
What you need to know as of September 2026
- The Supreme Court decided Bondi v. VanDerStok on March 26, 2025, reversing the Fifth Circuit and remanding the case. Justice Neil Gorsuch wrote the Court's opinion, joined by Chief Justice John Roberts and Justices Sonia Sotomayor, Elena Kagan, Brett Kavanaugh, Amy Coney Barrett and Ketanji Brown Jackson. Justices Clarence Thomas and Samuel Alito dissented.
- The 2022 ATF rule, Final Rule 2021R-05F, clarified when certain partially complete frames or receivers and weapon parts kits fall within the federal definition of a firearm.
- A commercially sold parts kit is not automatically a firearm simply because it is marketed as a "ghost gun kit." The federal definition depends on the characteristics of the kit and whether it is designed to or may readily be completed, assembled, restored or otherwise converted to expel a projectile.
- State laws can impose additional restrictions, including serialization requirements, restrictions on unfinished frames and receivers, and prohibitions on certain unserialized firearms.
- Federal law continues to allow individuals to make firearms for themselves in circumstances permitted by federal law, but state law may impose additional restrictions.
This article explains the federal framework, the Supreme Court decision, 3D-printed firearms, privately made firearms and important state-law developments.
Why Were Ghost Guns Historically Difficult to Regulate?
The federal Gun Control Act defines a firearm to include a weapon that is designed to or may readily be converted to expel a projectile by the action of an explosive, as well as the frame or receiver of such a weapon.
Before the 2022 ATF rule, disputes frequently centered on whether partially complete frames, receivers and weapon parts kits had reached the point at which they qualified as firearms under the statute.
The 2022 ATF rule addressed those questions by modifying the regulatory definitions of "firearm," "frame or receiver," "privately made firearm" and "readily."
The rule provides that a partially complete, disassembled or nonfunctional frame or receiver can fall within the federal definition when it has reached a stage of manufacture where it may quickly and easily, or "readily," be made to function as a frame or receiver.
At the same time, the rule expressly excludes raw materials such as a block of metal or liquid polymers and excludes a frame or receiver that has been destroyed.
That distinction is important because the legal status of an unfinished component cannot be determined solely by a marketing label such as "80% lower."
The 2022 ATF Rule
ATF Final Rule 2021R-05F, titled Definition of "Frame or Receiver" and Identification of Firearms, was signed on April 11, 2022, and took effect August 24, 2022.
The rule addressed several issues.
Frames and Receivers
The rule established a revised regulatory definition of a frame or receiver. A partially complete, disassembled or nonfunctional frame or receiver can qualify when it has reached a stage where it may readily be made to function as a frame or receiver.
The rule also clarified which component of a firearm is treated as the frame or receiver for marking purposes.
Weapon Parts Kits
The rule clarified that the federal definition of "firearm" can include a weapon parts kit that is designed to or may readily be completed, assembled, restored or otherwise converted to expel a projectile by the action of an explosive.
This was the central issue in Bondi v. VanDerStok.
Marking and Recordkeeping
The rule established additional marking and recordkeeping requirements for federal firearms licensees and addressed how FFLs handle privately made firearms that they acquire into inventory. ATF states that an FFL acquiring a PMF into inventory generally must mark it and maintain the required records.
What Did the Supreme Court Decide?
On March 26, 2025, the Supreme Court decided Bondi v. VanDerStok, 604 U.S. 458 (2025).
The case concerned whether the Gun Control Act's definition of "firearm" could encompass certain weapon parts kits regulated by ATF's 2022 rule.
The Supreme Court reversed the Fifth Circuit and remanded the case. The Court's opinion concluded that the Gun Control Act covers at least some weapon parts kits and that the ATF rule was within the statute's scope.
The decision did not establish that every unfinished firearm component or every product marketed as an "80% lower" is automatically a firearm.
Instead, the Court's reasoning focused on the statutory definition and whether particular kits or partially complete components fall within that definition.
The 7-2 Decision
The Court's majority consisted of:
- Chief Justice John Roberts
- Justice Neil Gorsuch
- Justice Sonia Sotomayor
- Justice Elena Kagan
- Justice Brett Kavanaugh
- Justice Amy Coney Barrett
- Justice Ketanji Brown Jackson
Justice Gorsuch wrote the opinion of the Court. Justices Clarence Thomas and Samuel Alito dissented.
Federal Ghost Gun Law in 2026
There is no single federal statute that simply says "ghost guns are illegal."
Instead, federal law regulates firearms, frames and receivers, certain weapon parts kits, transfers, manufacturing activity and particular categories of weapons.
Are Unfinished Frames and Receivers Federally Regulated?
Sometimes.
Under ATF's rule, a partially complete, disassembled or nonfunctional frame or receiver may be regulated as a firearm when it has reached a stage where it may readily be made to function as a frame or receiver. Raw materials and certain other unfinished items remain outside the definition.
That means the phrase "80% lower" does not itself determine the legal status of an item.
An unfinished receiver must be evaluated according to its actual characteristics and the applicable federal and state definitions.
Are Weapon Parts Kits Regulated?
Certain ones are.
Under Final Rule 2021R-05F, a weapon parts kit can fall within the federal definition of firearm when it is designed to or may readily be completed, assembled, restored or otherwise converted to expel a projectile.
Those products can therefore become subject to the federal requirements that apply to firearms, including requirements governing licensed dealers, transfers, records and background checks.
The Supreme Court's 2025 decision confirmed that the Gun Control Act can reach these qualifying parts kits.
Are All "80% Lowers" Federally Firearms?
No.
"80% lower" is a commonly used marketing term, not the federal legal test.
ATF's rule instead examines whether the item has reached the stage at which it may readily function as a frame or receiver.
Therefore, two products marketed with similar terminology could require separate legal analysis based on their actual characteristics.
Can You Make a Firearm at Home?
Federal law does not generally prohibit an individual from making a firearm for personal use solely because the firearm is privately made.
ATF recognizes privately made firearms and explains that individuals may make firearms for themselves when otherwise permitted by federal law. ATF also states that not all PMFs are illegal and that federal law does not require every firearm to have a serial number.
However, several limitations remain important.
A person who is prohibited from possessing firearms cannot lawfully possess or manufacture a firearm merely because it is privately made.
A person also cannot manufacture firearms as an unlicensed business when the activity meets the federal definition of being engaged in the business of manufacturing firearms.
State law may impose additional requirements or prohibit conduct that federal law permits.
3D-Printed Firearms
3D-printed firearms raise two separate legal questions:
- Whether the person may lawfully manufacture or possess the firearm.
- Whether the firearm satisfies federal requirements governing detectability.
Federal Detectability Requirements
18 U.S.C. § 922(p) prohibits the manufacture, importation, sale, shipment, delivery, possession, transfer or receipt of certain firearms that do not meet federal detectability requirements.
The statute addresses both metal-detector detectability and whether each major component produces an accurate image when inspected using airport-style X-ray equipment.
The statute therefore does not simply create a general rule saying that "3D-printed guns are illegal."
Instead, a 3D-printed firearm must comply with the applicable federal requirements, while state law may impose additional restrictions.
State Ghost Gun Laws
Federal law is only part of the analysis.
States have adopted different approaches to privately made firearms, unfinished frames and receivers, serial numbers, 3D-printed firearms and digital firearm manufacturing instructions.
Because these laws differ substantially, it is not accurate to assume that every state treats an unserialized firearm the same way.
Examples of State Restrictions
Maryland
Maryland's 2022 Public Safety - Untraceable Firearms law changed the state's definition of firearm to include certain unfinished frames or receivers and generally prohibits possession of a firearm on or after March 1, 2023 unless it is required by federal law to be, and has been, marked with the required number.
Nevada
Nevada law restricts the sale, transfer, possession, purchase and transportation of certain unfinished frames or receivers and separately addresses firearms manufactured or assembled without serial numbers. The statutes contain exceptions and establish different penalties depending on the offense.
Oregon
Oregon's HB 2005 established restrictions involving firearms without serial numbers, unfinished frames or receivers and undetectable firearms. The law includes different penalties depending on the offense and circumstances.
Illinois
Illinois law defines an unfinished frame or receiver using a standard that includes an item that has reached a stage where it may readily be completed, assembled or converted into a functional firearm. Illinois also restricts the sale, transfer and possession of certain unserialized firearms and unfinished frames or receivers, subject to statutory exceptions.
Vermont
Vermont's Ghost Guns Act prohibits the knowing possession of certain unfinished frames or receivers without the required serial number and prohibits possession of certain unserialized firearms and frames or receivers. The statute contains specified exceptions.
The key point is that state laws do not all use the same definitions, exceptions or penalties.
2026 State Legislative Developments
Several states continued to address 3D-printed firearms and firearm serialization in 2026.
Colorado
Colorado enacted HB26-1144, titled "Prohibit Three-Dimensional Printing Firearms & Components."
The law prohibits knowingly manufacturing or producing certain potentially functioning firearms or firearm components by 3D printing. The law contains exceptions for specified federally licensed manufacturers and accredited gunsmithing programs. The Colorado General Assembly identifies the enacted law as creating criminal penalties that can escalate for subsequent offenses.
This is a 2026 law and should not be identified as "HB 1144 (2025)."
Maine
Maine enacted LD 1126 / HP 745, titled "An Act Requiring Serial Numbers on Firearms and Prohibiting Undetectable Firearms."
The Maine Legislature lists the measure's final disposition as enacted January 11, 2026.
New Jersey
New Jersey's A4975 addresses firearm digital instructions and other conduct involving firearms without serial numbers. The legislation defines firearm digital instructions to include computer-aided design files or other code that can be used to program a 3D printer to manufacture or produce a firearm, receiver, magazine or firearm component.
Because state laws can change through legislation, court decisions and regulatory action, readers should verify the law applicable to their state before relying on a state-law summary.
What About 3D-Printed Firearms and Digital Design Files?
State restrictions increasingly address not only completed firearms but also the means of manufacturing them.
For example, New Jersey's statute addresses possession of firearm digital instructions by people who are not licensed or registered to manufacture firearms.
Colorado's 2026 law directly addresses 3D printing of certain firearms and firearm components.
This means a person cannot determine whether 3D-printed firearm activity is legal solely by looking at federal law.
What If You Already Own a Privately Made Firearm?
The answer depends on how and when the firearm was made, whether it is federally lawful, the firearm owner's status, and the law of the state where the firearm is possessed.
There is no universal federal rule requiring every privately made firearm to be surrendered or destroyed.
Likewise, there is no universal rule allowing an owner to add a serial number and automatically make an otherwise unlawful firearm legal.
State law can establish its own requirements for serialization, possession, transfer and disposition.
If you already possess a privately made or unserialized firearm and are uncertain whether it complies with current law, consult a qualified firearms attorney before transferring, transporting, modifying or disposing of it.
Can I Transport a Privately Made Firearm Across State Lines?
Interstate transportation requires separate analysis.
A destination state's law may impose restrictions that do not exist in the state where the firearm was made or acquired. Federal interstate-transfer and transportation rules may also apply depending on the circumstances.
It is not accurate to say that crossing state lines with an unserialized firearm automatically violates the federal Gun Control Act simply because the destination state restricts such firearms.
Before transporting a privately made firearm across state lines, verify both federal requirements and the laws of the states involved.
What Is the Difference Between a Ghost Gun and an 80% Lower?
The terms describe different things.
An "80% lower" is a commercial term commonly used for an unfinished receiver.
A privately made firearm is a firearm completed, assembled or otherwise produced by someone other than a licensed manufacturer.
A "ghost gun" is a common informal term generally used for a privately made or otherwise unserialized firearm.
An unfinished component is not automatically a firearm simply because it is marketed as an "80% lower." Its legal status depends on its characteristics and applicable federal and state law.
Are Ghost Guns Legal Federally?
There is no simple yes-or-no answer.
Federal law permits some privately made firearms, including firearms made by individuals for personal use, while regulating certain frames, receivers and weapon parts kits.
The 2022 ATF rule clarified when certain unfinished frames, receivers and parts kits fall within the federal definition of firearm. The Supreme Court upheld the rule's application to qualifying weapon parts kits in Bondi v. VanDerStok.
Whether a particular firearm or component is lawful depends on the facts and the applicable federal and state laws.
Can I 3D Print a Firearm?
Federal law does not categorically prohibit every instance of 3D-printing a firearm.
However, federal law imposes detectability requirements, and the person making or possessing the firearm must otherwise be legally permitted to possess it.
State law can be more restrictive.
Colorado, for example, enacted HB26-1144 in 2026 to prohibit certain 3D printing of firearms and firearm components, subject to specified exceptions.
Other states have adopted restrictions involving unserialized firearms, unfinished frames and receivers or firearm digital instructions.
What Should I Do If I Own an Unserialized Firearm?
Do not assume that federal law alone determines whether you can legally possess it.
Before selling, transferring, transporting, modifying or disposing of an unserialized firearm, determine:
- Whether the firearm qualifies as a privately made firearm
- When and how it was manufactured
- Whether federal law requires a serial number or other marking
- Whether you are legally permitted to possess it
- What the law of your current state requires
- Whether the law of another state applies if you intend to transport or transfer it
If the legal status is uncertain, consult a qualified firearms attorney before taking action.
Are 80% Lowers Still Legal?
There is no universal federal answer based solely on the phrase "80% lower."
Federal law does not use "80%" as the controlling legal standard. The relevant question is whether a particular unfinished frame or receiver meets the applicable definition under federal law.
ATF's rule includes certain partially complete frames and receivers that have reached a stage where they may readily be made to function as a frame or receiver.
State law may impose additional requirements or prohibit possession of particular unfinished frames or receivers.
What Does the Supreme Court Decision Mean for Gun Owners?
The practical significance of Bondi v. VanDerStok is that the federal government can apply the Gun Control Act to certain weapon parts kits that fall within the statutory definition of a firearm.
The decision does not mean:
- Every firearm part is federally regulated as a firearm
- Every "80% lower" is automatically a firearm
- Every privately made firearm is federally illegal
- Every unserialized firearm must be surrendered
- Every state treats privately made firearms the same way
Instead, the legal analysis depends on the particular firearm, component or kit and the applicable federal and state law.
What This Means for Legal Risk
Privately made firearms can create legal questions that depend heavily on jurisdiction and circumstances.
Potential issues can include:
- Whether a component legally qualifies as a firearm
- Whether a weapon parts kit is subject to federal regulation
- Whether a firearm requires a serial number
- Whether a person is legally permitted to possess the firearm
- Whether a state prohibits possession of an unserialized firearm
- Whether a state regulates 3D-printed firearms or firearm digital instructions
- Whether interstate transportation or transfer is lawful
Because the rules vary by jurisdiction and continue to change, legal status should be evaluated under the law applicable to the specific firearm and circumstances.
Frequently Asked Questions
Did the Supreme Court Rule on Ghost Guns?
Yes. On March 26, 2025, the Supreme Court decided Bondi v. VanDerStok, holding that the Gun Control Act covers at least some weapon parts kits and reversing the Fifth Circuit's judgment. The case was remanded for further proceedings.
Did the Supreme Court Make All Ghost Guns Illegal?
No.
The decision addressed whether the Gun Control Act covers certain weapon parts kits regulated under ATF's 2022 rule. It did not establish that every privately made firearm is illegal or that every unfinished firearm component qualifies as a firearm.
Are Ghost Guns Legal Federally?
Some privately made firearms are lawful under federal law, while other firearms, frames, receivers and parts kits are subject to federal regulation.
The answer depends on the firearm's characteristics, how it was made, how it is being transferred or possessed, and the person's legal status.
Can I Build a Firearm at Home?
Federal law generally allows an individual who is legally permitted to possess firearms to make a firearm for personal use, subject to applicable federal requirements.
State law may impose additional restrictions.
Are 80% Lowers Legal?
"80% lower" is not the federal legal test.
Whether a particular unfinished receiver qualifies as a firearm depends on its characteristics and whether it meets the applicable federal definition. State law can impose additional restrictions.
Can I 3D Print a Firearm?
Federal law does not categorically prohibit all 3D-printed firearms, but federal detectability requirements apply and the person must otherwise be legally permitted to possess the firearm.
Some states impose additional restrictions. Colorado, for example, enacted HB26-1144 in 2026 addressing 3D-printed firearms and components.
Do Privately Made Firearms Need Serial Numbers?
Not every privately made firearm is subject to the same federal marking requirements.
ATF states that not all PMFs are illegal and that not all firearms are required to have a serial number. Requirements can apply when a PMF is acquired into the inventory of an FFL or under applicable state law.
What If My State Has a Ghost Gun Law?
State laws vary.
Some states restrict possession of unserialized firearms. Others regulate unfinished frames and receivers, require serialization, regulate 3D printing or restrict firearm digital instructions.
A federal law analysis does not replace a state-law analysis.
What Should I Do If I Am Unsure Whether My Firearm Is Legal?
Do not rely on a general internet definition of "ghost gun," "80% lower" or "unserialized firearm."
Determine the applicable federal and state requirements for the specific firearm and circumstances. If there is uncertainty, consult a qualified firearms attorney before transferring, transporting, modifying or disposing of the firearm.
The Bottom Line
The Supreme Court's 2025 decision changed the legal landscape for certain commercially sold weapon parts kits, but it did not create a blanket federal ban on privately made firearms.
Federal law distinguishes between raw materials, unfinished components, frames and receivers, qualifying weapon parts kits and completed firearms. ATF's 2022 rule provides the regulatory framework for making those distinctions, while Bondi v. VanDerStok confirmed that the Gun Control Act reaches at least some weapon parts kits covered by the rule.
State law adds another layer. Maryland, Nevada, Oregon, Illinois, Vermont and other jurisdictions have adopted restrictions involving unserialized firearms, unfinished frames or receivers or related manufacturing activity.
The most important point for gun owners is simple: the legal status of a privately made firearm cannot be determined from the term "ghost gun" alone.
The specific firearm, how it was made, when it was made, who possesses it and the law of the applicable jurisdiction all matter.
Right To Bear and Self-Defense Legal Protection
Ghost gun laws can create legal questions during firearm-related incidents, particularly when questions arise about possession, manufacturing, serialization or the legality of a firearm.
Right To Bear is a self-defense legal protection membership organization. Members have access to legal support for covered self-defense incidents, subject to the terms, conditions and exclusions of the membership and applicable policy.