is a marking on the base of a cartridge case
. It is typically pressed into the metal, and contains various information about the ammunition
. Some information that might be included:
- Cartridge type
- Manufacture date
Some or none of these may be present. Much military ammunition is headstamped with the manufacturer and a year so that it may be determined if the ammunition is safe or effective to use. The manufacturer name may be pressed in full, or it may be represented by one to four letter codes. A quick search of the internet will turn up exhaustive reference lists of these manufacturer codes.
As an example, on the .30-06 Springfield ammunition I'm presently learning to reload I have run across a number of codes. This is all ex-United States Military or allied military ammunition.
...and there are many others. In the case of surplus .30-06 Springfield
the year is important - the U.S. military used corrosive primer
s in this ammunition (M2 Ball
) up through the early 1950s. Generally, if you run across ammunition headstamped earlier than 1952 or so, you might want to consider either reloading it or being sure to clean your rifle thoroughly immediately after firing.
The earliest case I've seen was a S A / 4 - a Springfield Armory case from 1904! I just formed, cut and reloaded it, and I expect to shoot it.