headstamp

A headstamp is the markings found on the base of a cartridge case. It identifies the cartridge’s origin, type, and often its production date or lot number. Headstamps are stamped during manufacture by the ammunition maker and may include the caliber or cartridge designation.

The most common elements are the manufacturer’s name or logo, a caliber designation, and a year or lot code. Some headstamps include proof marks, military acceptance stamps, or symbols. The arrangement varies by maker; on many centerfire cartridges the marks appear around the primer pocket in one or two lines. Military and civilian ammunition often use different conventions, with military headstamps sometimes following standardized codes and civilian marks reflecting brand identity.

Headstamps serve to distinguish commercial from military ammunition and to provide traceability for quality control, safety, and forensic analysis. They also help identify ammunition in collections or field recoveries. Dating can be straightforward when an explicit year is included, or it can require reference to catalogs or records when a code is used.

Dating and cataloging: Some headstamps include an explicit year; others use coded marks that require reference lists or catalogs. Older or rarer headstamps may reflect discontinued brands, factory changes, or corporate mergers, which can complicate dating.

Collectors and researchers study headstamps to identify origin and era. Numerous reference works document known marks, and catalogs compile widely used manufacturer codes. While headstamps are a valuable clue, precise dating often depends on corroborating cartridge design, case style, and historical production data.