How to Check a Firearm Serial Number: Stolen, Altered, or Missing

To check a firearm serial number, locate the number on the frame or receiver, look it over for signs of tampering, and ask your local police department to run it through the FBI’s National Crime Information Center to see whether the gun has been reported stolen. That NCIC check is the only reliable way to confirm a firearm isn’t stolen, and private citizens can’t run it themselves.¹

Where to Find the Serial Number

Federal law treats the frame or receiver as the firearm itself, and that’s where the serial number lives.² Exactly where depends on the type of gun:

On semi-automatic handguns, check the frame near the trigger guard first. The number often appears again on the slide or inside the ejection port.
On revolvers, look at the frame with the cylinder swung open. Older revolvers sometimes hide the number under the grip panels.
On rifles and shotguns, the receiver is the usual spot, though some makers also stamp the barrel.

Many firearms carry matching numbers on more than one part. When they don’t match, the gun may have replacement parts, or it may have a history worth investigating. Wipe away oil, dirt, and carbon buildup and use good light; worn engravings become legible more often than people expect.

Reading the Engraving for Signs of Tampering

Federal rules require serial numbers to be engraved at least .003 inches deep, with characters no smaller than 1/16 of an inch, placed so they resist easy removal.³ What you’re looking at should be uniform in depth, spacing, and font. Grinding marks, re-stamped characters, unusually shallow engraving, mismatched fonts, or an area where the metal surface looks different from the surrounding frame all point to tampering. So does a blank space where a number should be.

Federal law also requires the manufacturer’s name or recognized abbreviation, the model designation if there is one, and the caliber or gauge to appear on the frame or receiver alongside the serial number.⁴ Missing or inconsistent markings are another warning sign.

How to Check Whether the Gun Is Stolen

Ask Your Local Police

Call your local police department, give them the serial number, and ask them to run it through NCIC. The National Crime Information Center is an FBI-maintained database of stolen property, including firearms, and it’s accessible to criminal justice agencies at every level of government.¹ Most departments do this at no charge. Some handle the request over the phone; others ask you to come in, sometimes with the firearm.

Access to NCIC is restricted to authorized criminal justice agencies.⁵ No app, website, or paid service gives private individuals real-time NCIC results, regardless of what it advertises.

What the ATF Does and Doesn’t Do

The ATF’s National Tracing Center is the only federal facility that traces crime guns, following a firearm from manufacturer through the distribution chain to the first retail purchaser. Traces are initiated exclusively by law enforcement during investigations, not by private citizens.⁶ You cannot request a trace on a gun you’re thinking of buying.

State and User-Submitted Databases

A handful of states run publicly searchable stolen-property databases that include firearms. These let you check a serial number against thefts reported within that state, but they won’t catch a firearm stolen elsewhere.

Some websites also let gun owners voluntarily report stolen firearms. A quick search there costs nothing, but coverage depends entirely on victims knowing about the site and submitting their information. A clean result on a user-submitted database is not proof the gun isn’t stolen. Treat it as one data point.

Before You Buy a Used Gun

Private sales are where this matters most, because you lose the safeguards that come with buying from a licensed dealer.

Inspect the serial number in person before you agree to anything. Uniform depth, spacing, and font; no grinding marks or re-stamps.
Write the full serial number down before money changes hands. You need it to run checks.
Ask the seller for documentation: original bill of sale, a receipt from a dealer, or prior registration paperwork. Missing paperwork isn’t proof of anything wrong, but it removes a layer of verification.
Call your local police with the serial number and ask them to check NCIC before you complete the sale.
Consider running the transfer through a Federal Firearms Licensee. Many FFLs will facilitate private sales for a fee, run a background check on the buyer, and verify the serial number through their own channels.

A seller who pressures you to skip these steps, or won’t let you record the number in advance, is telling you something. Legitimate sellers have no reason to object to a buyer’s due diligence.

If the Serial Number Is Missing or Altered

It is a federal crime to knowingly possess a firearm whose serial number has been removed, obliterated, or altered, as long as the gun has at some point moved in interstate commerce, which covers nearly every commercially produced firearm.⁷ The government has to prove you knew the number was tampered with, but visible grinding marks or an obvious blank space make that easy to show. The penalty is up to five years in federal prison, a felony conviction that also permanently costs you the right to own firearms.⁸

If you encounter a firearm with a missing or altered number during a potential purchase, don’t take possession of it. Contact your local police, describe what you saw, and let them handle it.

If you already own a gun and discover its serial number appears to have been tampered with, contact law enforcement right away. Voluntarily reporting the situation and cooperating shows good faith, which matters if questions come up later about what you knew.

Serial numbers that are simply worn or faded from age are a different situation. Wear from decades of use is not the same as deliberate obliteration, and a qualified gunsmith or a law enforcement forensic lab can often recover faded numbers. The ATF also runs an Obliterated Serial Number Program that uses forensic techniques on numbers that have been ground off.⁶

Guns That May Not Have a Serial Number

Not every firearm is required to carry a modern serial number, so the absence of one isn’t automatically suspicious.

Federal law defines an “antique firearm” as one manufactured in or before 1898, along with certain replicas that can’t fire modern ammunition and muzzle-loading black powder firearms.⁹ Antique firearms are largely excluded from the Gun Control Act’s requirements. A genuine pre-1899 revolver or rifle may have no serial number, or one in a format nothing like the modern standard, and that’s legal.

Privately made firearms, sometimes called ghost guns, are the other category. Federal law lets an unlicensed individual build a firearm for personal use without adding a serial number. Under a 2022 ATF rule, once such a gun enters commercial channels, any Federal Firearms Licensee who takes it into inventory has to mark it with a serial number within seven days of receipt or before selling it, whichever comes first, with the dealer’s abbreviated license number as a prefix.¹⁰³ The rule doesn’t require unlicensed individuals to serialize firearms they build for their own use, though some states have their own requirements.

1
Federal Bureau of Investigation. National Crime Information Center (NCIC)
2
eCFR. 27 CFR 478.12 – Definition of Frame or Receiver
3
eCFR. 27 CFR 478.92 – Identification of Firearms and Armor Piercing Ammunition by Licensed Manufacturers and Licensed Importers
4
eCFR. 27 CFR Part 479 Subpart G – Registration and Identification of Firearms
5
Air Force Office of Special Investigations. NCIC Info Sheet
6
Bureau of Alcohol, Tobacco, Firearms and Explosives. National Tracing Center
7
Office of the Law Revision Counsel. 18 USC 922 – Unlawful Acts
8
Office of the Law Revision Counsel. 18 USC 924 – Penalties
9
Office of the Law Revision Counsel. 18 USC 921 – Definitions
10
Bureau of Alcohol, Tobacco, Firearms and Explosives. Final Rule 2021R-05F – Definition of Frame or Receiver and Identification of Firearms Overview