People in the United States have been making their own guns for centuries. The practice is deeply rooted in our constitutional history and tradition. Legal scholars have recognized that the Second Amendment's guarantee of the right to keep and bear arms would be meaningless in practice unless the government gave individuals the ability to exercise that right—which includes making their own guns.
For the past almost half-century, however, the sale and subsequent control of firearms have been heavily regulated by federal law. It might come as somewhat of a surprise that even in this era of regulation, it's still completely legal to make and own a homemade gun (also called a self-assembled or privately made gun). Even more surprising, in most states, a gun made wholly or even twenty percent at home need not be registered, and the owner need not pass a background check or obtain a license.
The United States Supreme Court has held that ordinary, law-abiding citizens have a Second Amendment right to keep a gun at home for self-defense and to carry a handgun in public for self-protection. (District of Columbia v. Heller, 554 U.S. 570 (2008); New York State Rifle & Pistol Association v. Bruen, 597 U.S. __ (2022).)
However, the Court has also acknowledged that the Second Amendment does not confer an unlimited right, and that lawmakers can still impose regulations, such as forbidding some people from possessing them (felons, for example); prohibiting them in places such as schools and government buildings; and imposing conditions and qualifications on their sale, licensing, and regulation.
The federal Gun Control Act of 1968 (GCA) requires, among other things, that persons "engaged in the business" of dealing in firearms be licensed by the federal government. This law made it illegal for an unlicensed person to make a firearm for sale or distribution. In addition, the law requires firearms dealers to perform background checks on people who want to buy a gun, and to maintain records of all gun sales. (18 U.S.C. § 921(a)(21)(C);18 U.S.C § 922(t); 18 U.S.C. § 923 (2022).)
However, nothing in the GCA prohibits individuals from making guns for their own personal use. A non-licensed person may make a firearm, provided it's not for sale and the maker is not otherwise prohibited from possessing firearms. (18 U.S.C. § 922 (d) (2022).) Federal law imposes none of the purchase restrictions on non-licensed possessors that it does on those who need licenses, and as a result, the homemade gun owner need not undergo a background check, and the gun doesn't have to be registered unless a state law requires registration. (For more information on state laws regulating ghost guns, see the section below "Are Ghost Guns and 3D Printed Guns Legal?")
Although the federal government has not regulated homemade guns (with minor exceptions), state governments and local municipalities (cities, towns, and unincorporated areas) can regulate them as long as the regulations don't conflict with federal law. A growing number of states have passed laws regulating homemade guns. (See "Are Ghost Guns and 3D Printed Guns Legal?" below) Several cities have also imposed their own regulations, including New York, Los Angeles, San Francisco, and Denver.
People convicted of felonies, as well as some kinds of misdemeanors, can't legally possess a gun—homemade or otherwise. Federal law prohibits gun possession by anyone convicted of a felony or domestic violence misdemeanor. Some states have additional prohibitions. California, for example, also forbids gun possession by people who know they have an arrest warrant for a felony, and people convicted of certain misdemeanors in the past 10 years (including simple assault or battery, and domestic violence crimes). (18 U.S.C. § 922(g) (2022); Cal. Penal Code §§ 29800, 29805 (2022).)
A person's criminal history is not the only factor that can lead to losing the right to possess a gun. Federal law prohibits gun ownership by people who are subject to domestic violence restraining orders (imposed after a hearing), illegal drug users, mentally ill (if determined by a judge), immigrants who have entered the country unlawfully, dishonorably discharged former members of the military, or fugitives from justice (people who are on the run from the law). States often add to that list: For example, California bans gun possession by people subject to various types of temporary restraining and protective orders, including not only domestic violence protective orders, but anti-harassment restraining orders, and gun violence restraining orders under California's "red flag law." (18 U.S.C. § 922(g) (2022); Cal. Penal Code §§ 18150, 29825 (2022).)
While it has always been legal for people to make homemade guns, in practical terms the process hasn't been so easy. A gun is a highly machined piece of equipment, dependent on precise specifications and materials. Most individuals making firearms at home historically lacked the equipment and know-how necessary to make a sophisticated piece of weaponry. However, modern technology has addressed many of these challenges, by offering "partial receivers" and the ability to make a gun using 3D printing.
A gun's "receiver" is the part of the firearm that houses the mechanical components and projects the bullet. Someone using a finished receiver could assemble a functioning firearm by adding necessary additional parts, such as the stock, barrel, trigger component, and magazine.
Because the GCA includes finished receivers in its definition of regulated firearms, a person buying a finished receiver would have to get it from a licensed firearms dealer. In addition, the person must pass a background check and register the firearm. A finished receiver has a serial number that can be used to trace the receiver to the registered owner.
A person interested in avoiding a background check and gun registration can instead buy an unfinished receiver (also called an 80%, blank, or partial receiver) to make a "ghost gun" (so called because it can't be traced). An unfinished receiver is a partially completed receiver that requires additional tooling to be fully completed. This kind of receiver is not technically a firearm and is not regulated by the GCA (and so does not bear a serial number). Unfinished receivers are legal to sell in most states and are widely available online and at gun shows.
Unregulated receivers can be converted into working firearms by someone with very basic skills and tools. A purchaser uses a drill press to create holes in the receiver and adds other parts to make a fully functional gun. Finishing kits and how-to guides are extensively available online and through specialty markets. Many sellers host "building parties," where buyers come together to share tools and expertise and assemble their firearms. Ghost guns created with unfinished receivers range from basic handguns to semi-automatic weapons.
Individuals purchasing an unfinished receiver or a kit to complete the assembly of a ghost gun are not subject to traditional background checks, and are not restricted by criminal or mental health history. Additionally, there are no sales records of 80% receivers and as a result, when a gun of this type is used in a crime, federal authorities can't get information about buyers from stores that sell guns. Unless a state law requires serial numbers for homemade guns (see "Are Ghost Guns Legal," below), the guns themselves are untraceable because their receivers don't have serial numbers.
People can also make homemade firearms using 3D printers. 3D printing, also known as "additive manufacturing," is a process whereby a three-dimensional model designed on a computer becomes a three-dimensional solid object as the printer lays down successive layers of material that conform to the programmed instructions. Gun parts, predominately made of plastic, can be generated from 3D printers.
3D printers are widely commercially available at relatively modest prices. As is true for their ghost gun cousins, instructions, guides, and highly detailed schematics for how to create 3D printed guns are readily available on the internet, generally from anonymous sources. And like ghost guns, 3D-printed guns require no background checks, serial numbers, or registrations, unless they're possessed in a state that has such requirements.
While it is not illegal under the GCA to print and make a gun in one's home, there is a catch: Because the Undetectable Firearms Act makes illegal any firearm that cannot be detected by a metal detector, every firearm must contain some amount of metal. But most 3D-printed guns are made of plastic. This means that a plastic 3D-printed firearm must have a metal plate inserted into the printed body. Such a requirement is difficult to enforce, however, because these firearms bear no serial number and are not registered unless required by state law. The opportunities to inspect these firearms and enforce the metal rule are practically nil.
As long as they are intended for personal use and have a detectable metal component, homemade guns are exempt from federal regulation. In 2013, a federal House Bill that was intended to ban unfinished receivers used to create assault weapons failed to pass (H.R. 2910).
Since then, some states have passed laws that regulate untraceable homemade guns. California became the first state to require registration: Anyone who makes or assembles a gun (ghost gun or 3D printed) must first apply for a serial number or other identifying mark from the state Department of Justice. Everyone who already owns a homemade gun or an unfinished receiver or other "firearm precursor" must apply for a serial number or identifying mark by January 1, 2024. Among other things, the law also forbids the sale or transfer of a homemade gun, and requires firearm precursors to be sold only through licensed dealers in most circumstances (by forbidding anyone without a license to sell more than one precursor in a month). Violations can be charged as misdemeanors. (Calif. Penal Code § 29180 (2022).)
The growing number of states that have similar laws regulating ghost guns, 3D printed guns, or both, include Connecticut, Delaware, the District of Columbia, Hawaii, Illinois, Nevada, New Jersey, New York, Rhode Island, Virginia, and Washington.
To learn more about the legality of 3D-printed guns, see Are 3D Printed Guns Legal?
Anytime you're facing a charge for unlawful gun possession, or want to know whether a state's laws allow you to possess a particular kind of gun, you should talk to an experienced criminal defense lawyer in your area. Violations of gun laws can result in years in prison. An experienced attorney can advise you about your rights and ensure you're protected.