Ejector Mark
Definition
A striated or impressed feature left on the cartridge case rim or base by the ejector pin at the moment of case ejection. Typically located at the 9 o'clock position in right-hand-ejection semi-automatic designs.
- Location on case
- Rim or base
- Cause
- Ejector pin contact during ejection
- Typical position
- 9 o'clock, right-hand ejection
- Mark type
- Striated or impressed
Common questions
How does an ejector mark differ from a firing pin or breech face mark?+
A firing pin mark forms at the primer during ignition and a breech face mark forms during the moment of firing when the case is pressed back against the bolt, while an ejector mark forms later, at the point of ejection, when the pin strikes the case as it pivots out of the action.
Why is the clock position of an ejector mark forensically useful?+
The position is influenced by the firearm's mechanical design, so a consistent clock position across recovered cases can support that they were fired from the same class of firearm, and individual toolmarks within the mark can support a match to one specific firearm.
Related terms
- AFTE Theory of Identification
- The Association of Firearm and Tool Mark Examiners' standard (1992, revised 2011) for reporting tool-mark comparison conclusions as Identification, Inconclusive, or Elimination...
- Breech Face
- The forward surface of the bolt, slide, or breech block that seals the chamber and contacts the cartridge case head during firing....
- Extractor Mark
- Striations or impressed features on the extractor groove of the cartridge case, produced by the spring-loaded extractor claw during the extraction stroke....
- Firing-Pin Impression
- The indentation left in the primer cup by the firing-pin tip at the moment of discharge. Its shape (circular, oval, rectangular), size,...
- Headstamp
- The manufacturer identification and calibre marking stamped into the base of a cartridge case during manufacture. Includes manufacturer codes, year, NATO cross...
- IBIS BrassTRAX-3D HD
- Forensic Technology's automated ballistic correlation system for cartridge cases. Captures topographic maps of the breech-face, firing-pin, and ejector areas and ranks case-to-case...
- Magazine-Lip Marks
- Parallel striated marks on the cartridge case below the extractor groove, produced by the magazine lips as the cartridge is stripped from...
- NABIS
- National Ballistics Intelligence Service; the UK police intelligence service that maintains a national headstamp and firearm reference collection and coordinates ballistic intelligence...
- NIBIN
- National Integrated Ballistic Information Network. ATF-operated distributed network of IBIS acquisition sites and correlation servers across the United States, active since 1999...