Ghost gun

"Ghost gun" is a term, used mainly by gun-control advocates and officials, for a privately made firearm without a serial number. Many are built from kits containing an unfinished frame or receiver, sometimes called an "80 percent" receiver, that the buyer completes with simple tools, and some are produced with 3D printers or CNC machines.

Federal law requires licensed manufacturers to put serial numbers on firearms, but individuals may legally make firearms for personal use, and kits of unfinished parts were not regulated as firearms by the ATF for many years. In 2022, the ATF issued a rule that treats certain kits and partially completed frames and receivers as firearms, requiring serial numbers and background checks on kits sold by dealers. The Supreme Court upheld the rule in Bondi v. VanDerStok (2025), rejecting a facial challenge. Many states have also passed laws regarding them.

Supporters of regulation say that untraceable guns are attractive to people who cannot pass a background check and complicate investigations, and that recovered ghost guns have increased in police seizures. Opponents point to the long American tradition of homemade firearms, argue that the ATF exceeded its authority and say that criminals will find other means, and that the rule burdens hobbyists. See also universal background checks.