There is no serial number on the gun

The lookup needs at least one digit to compare against a chart. If the only markings you can find are letters, or there is nothing at all where you expected a number, that is a real situation — and for a large part of firearms history it was the normal one.

Why a firearm can legitimately have no serial number

In the United States, serial numbers were not required on firearms until the Gun Control Act of 1968, which applied the requirement to firearms manufactured or imported from 22 October 1968. Before that date, numbering was a commercial decision. Many makers numbered their products; many did not number low-cost guns at all.

So an unnumbered gun is not automatically suspicious, and it is not automatically old. Inexpensive .22 rimfires, utility shotguns and wartime production runs are the common cases: a maker who was shipping tens of thousands of a cheap model had little reason to engrave a number nobody had asked for.

You are probably looking at a different marking

Firearms carry many stamped or engraved markings that look like serial numbers and are not. The letters you can read are usually one of these:

• Inspector or acceptance stamps — single letters or short letter groups applied by a government inspector, often on the barrel or receiver. On military arms these are common and can be mistaken for a code.
• Proof marks — applied when a barrel is proof-tested. British, German (nitro), Belgian and Italian proof marks are their own system with their own meanings, and they do not date the firearm by themselves.
• Assembly or fitter's numbers — used during manufacture to keep parts of one gun together. They are often short, often appear on several parts, and were never meant to identify the gun.
• Import marks — applied by the importer on guns brought into a country, sometimes on the barrel, sometimes as a small added line of text.
• Model and calibre markings — the maker's name, the model, the chambering. Text, not a serial.

A real serial number is normally the deepest, clearest and most deliberate stamping on the receiver or frame, and on a modern gun it is the one a dealer would record. If a marking is shallow, uneven, or looks like an afterthought, it is more likely one of the categories above.

How to date a firearm that has no serial number

Without a number, serial charts cannot help — and no honest tool should pretend otherwise. Dating then rests on the features of the gun itself:

• The maker's name and address as stamped, which dates the marking because addresses and company names changed.
• The model name and the period that model was catalogued.
• Proof marks and their era, where present.
• Patent dates, which are common on older American arms.
• Roll-stamped decorative patterns and the presence or absence of a rollmark — the style changed by decade.
• The manufacturer's own catalogue history and, for military arms, acceptance records.

If you want to be certain

Several makers and museums maintain records and will search them for a fee, issuing a letter of authenticity. That letter is the document an insurer, an auction house or a transferee will accept. Our guides on the individual makers say which of them still do this and where the records are held.