Unless you buy a gun brand new, there is a risk that the weapon may have been stolen or used in a crime. The easiest way to check a gun's history is to obtain the serial number from the body of the gun and then ask a gun professional to run a stolen weapons search. Some websites also have searchable public databases of stolen registered weapons.
Locate the Serial Number
Every registered gun has a serial number associated with it. You can find this listed in the owner's manual and plainly printed on the body of the gun, usually on the handle, trigger guard, slide or receiver. Licensed firearms dealers such as gun stores and pawn shops are obligated to keep records of the firearms they sell. You could also contact the dealer and see if it has a record of the serial number. If the dealer has gone out of business, contact the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). The ATF keeps the firearms sales records of licensed dealers who have gone bust.
Run a Police Search
The local police department or sheriff's office can run a gun serial number search for you using the national ATF eTrace database. Police records will indicate whether the gun was reported lost or stolen or was used in a crime. Some law enforcement departments – for example, the Florida Crime Information Center – provide a free online search tool for stolen property within the state. Visit the law enforcement website of your state to see if it offers this service.
Ask the Internet
The HotGunz Stolen Firearms Database maintains a free, searchable database of stolen firearms (see Resources). Enter the gun's serial number without spaces, dashes or other special characters in the "Search the Stolen Gun Database" box. HotGunz is a user-submitted database, which means that gun owners self-report the information that their firearms were lost or stolen. Searching the database is quick and easy, but it isn't a substitute for an official police check.
Vintage guns may not have serial numbers printed on their bodies. Identify the gun's make and model by visiting the manufacturer's website; there may also be tips there as to where to find the serial number. For a fee, an antique gun dealer or gun shop might also be able to run a basic search on the history of the gun. Sometimes a lineage of previous owners can be composed, and you should be able to figure out the age and primary use of the gun.
What to Do With a Bad Weapon History
It is illegal for dealers to sell guns that were stolen or lost or are wanted by law enforcement. If you discover that a firearm has a suspicious history, report it to the police. As a responsible gun owner, you might also add the serial number to the HotGunz database. You should also report any gun that doesn't have a serial number printed on its body. A filed-off or worn serial number is a strong indicator of a stolen gun.