Upon locating or acquiring an old firearm you want to learn as much about it as possible. Below is some information on how to go about deciphering the various markings your firearm carries.
Serial Number Location
The most pervasive identification mark on your firearm is the serial number. The serial number is stamped on just about every major component of the firearm which allows you to confirm how original your assembly is.
Typical Location of Serial Number:
- Water Table / Receiver
- Bottom of Barrels
- Inside of Trigger Guard
- Inside of each Lock Plate
- Stock (Under Trigger Guard)
- Forearm Iron
- Forearm Wood
Pete Mikalajunas maintains a listing of serial numbers in an attempt to identify dates of manufacture
Model Identification
Typically located on the other side of the of the water table and usually a two digit number. In this example the fiream is a model 58.
Barrel Specification
The water table will also indicate barrel information. The marking (usually in the vicinity of the serial number) is a letter followed by a two digit number (for example T28 or D30). This code indicates the type of barrels and length (in inches) that were used on the firearm.
Barrel Codes are::
- S – Steel
- T – Twist
- K – Krupp
- D – Damascus
- C – Chain Damascus
So a stamping of T28 indicates that the firearm was made with 28 inch Twist barrels. C30, as in the sample below, indicates 30 inch Chain Damascus.
The bottoms of the barrels may also be stamped with the first portion of the barrel code. For example steel barrels will be stamped ‘S’.
Visually, the differences between the types of barrels can be easy to discern unless the barrels are heavily rusted or have been re-blued without the remaining processes to expose the laminated steel.



