Serial numbers are located in various places on guns, depending on the manufacturer and type of weapon. The most common location for serial numbers is on the bottom of the gun butt or on the inside of the frame. Before looking for the serial number, first ensure that the gun is not loaded, and then follow proper gun safety regulations.
According to the United States Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), federal law requires that all guns made or imported into the United States are imprinted with a serial number. Records of these numbers are kept by firearm manufacturers and dealers. In the event of a crime, law enforcement can use a serial number to trace a gun's owner and identify a gun that has been stolen, sold or discarded.
The ATF suggests that when a serial number is illegible, is visibly worn or appears severely damaged, owners should consult a local law enforcement department because a filed-down serial number may indicate a stolen gun.