The Second Amendment protects an individual's right to keep and bear arms. While this fundamental right remains protected, a person's actual ability to buy, sell, and possess firearms in this country is highly regulated. This is why it may come as a surprise to many that it is entirely legal to make and own a homemade gun.
Federal law, under The Gun Control Act of 1968 (GCA), requires that persons "engaged in the business" of dealing in firearms must be licensed in order to do so. This makes it illegal for an unlicensed person to make a firearm for sale or distribution. In addition to licensing requirements, the law mandates that firearms dealers perform background checks on anyone purchasing a firearm and maintain records of all gun sales. This enables the government to keep track of all the firearms legally in circulation.
These requirements do not apply, however, if an individual makes a gun for his or her own personal use. As long as the firearm is not for sale and the individual is not otherwise prohibited from possessing a firearm (like a convicted felon), a person can create a homemade firearm without being subject to a background check, and that firearm does not have to be registered with any governmental or law enforcement agency. (Note, however, that California requires new and existing guns to be registered as of 2018.)
In the landmark decision District of Columbia v. Heller, the U.S. Supreme Court held that the Second Amendment protects an individual's right to possess a firearm unconnected with service in a militia, and to use that firearm for lawful purposes, such as self-defense within the home. (554 U.S. 570 (2008).) However, the Court also determined that the Second Amendment is not an unlimited right and is not a right to keep and carry any weapon in any matter for any purpose. For this reason, the Court's opinion did not cast doubt on various gun regulations, such as the prohibition on the possession of firearms by felons and the mentally ill; laws forbidding firearms in places such as schools and government buildings; and various laws imposing conditions and qualifications on the sale, licensing, and regulation of firearms.
Homemade firearms—those made from unfinished receivers as well as with 3D printers—present a new challenge for lawmakers as they sort through balancing an individual's right to possess a firearm with public concern for safety. Recent federal legislation seeking to impose licensing and registration requirements on homemade weapons failed to be enacted, with the exception of the extension of the existing Undetectable Firearms Act for an additional ten years (which makes illegal any firearm that cannot be detected by a metal detector).
In the absence of federal directives, both state governments and local municipalities can impose laws regarding homemade firearms, as long as those regulations do not conflict with existing federal law. California requires registration as of 2018. Several municipalities have attempted to impose restrictions on the creation and possession of homemade firearms. In 2013, the city of Philadelphia did succeed in banning the making or owning of 3D-printed guns by anyone not in possession of a federal firearms manufacturing license.
New York City also considered legislation in 2013 requiring a gunsmith license in order to make 3D-printed guns. The legislation also required all 3D-printed guns to be registered after creation. Around the same time, Washington D.C. attempted to ban 3D-printed guns in their entirety. Neither of these measures has been enacted.
As the technology relevant to homemade guns becomes more readily accessible (for example, 3D printers are quickly becoming less expensive and more available), it is likely that legislation at the local level will become more prolific.
To learn more about homemade guns, see our article Homemade Guns: Are They Legal? Must They Be Registered?
In the United States, no individual has yet been prosecuted for the otherwise legal creation or possession of a homemade gun. Of course, any criminal activity using a homemade firearm is subject to appropriate prosecution for that behavior. A tragic example of an individual using a homemade weapon in a crime occurred in 2017 when a gunman killed five people in California with a homemade assault rifle. Additionally, an individual may be criminally liable for the creation or possession of a homemade gun if that individual is prohibited from possessing firearms in general. For example, convicted felons and individuals with domestic violence convictions are prohibited from having a homemade gun because such an individual cannot possess any firearms.
While no criminal prosecutions have occurred for creating or possessing homemade guns, the federal government did take action in the early days of 3D-gun printing. In May 2013, the non-profit organization Defense Distributed released an online video of a successful test shoot of the first functional 3D-printed gun, called The Liberator. Days later, the government ordered Defense Distributed to remove the digital files containing the gun's schematics, which were also posted online. Citing The International Traffic in Arms Regulations (ITAR), the State Department asserted that the online presence of the design potentially violated international export controls. Defense Distributed complied with the directive and was not prosecuted.
As the manufacturing technology evolves to enable quicker production of more lethal firearms, however, the law may also evolve. While efforts to ban 3D-printed guns in their entirety have not been successful, Congress recently extended the existing Undetectable Firearms Act, which requires that all firearms contain a piece of metal (so that they are detectable by a metal detector). This requires that guns made entirely from plastic have a metal plate inserted into the body of the firearm. Additionally, states may begin to require the registration of these firearms.
Several countries outside the United States have criminalized the mere possession of 3D-printed firearms. For example, the United Kingdom banned all unregistered firearms created by 3D printers. Likewise, it is currently illegal in Japan to possess a firearm made from a 3D printer. In October 2014, a Japanese man became the first person sentenced to prison (a term of two years) for downloading and printing five plastic guns.