- 01: Introduction
- 02: History
- 03: Propellants, Firearms, and Ammunition Development
- 04: Modern Firearms Manufacture
- 05: Small Arms Ammunition
- 06: Evidence Handling Procedures
- 07: Equipment and Instrumentation
- 08: Examination of Firearms
- 09: Cartridge and Shotshell Examination
- 10: Characterization and Evaluation of Fired Projectiles
- 11: Bullet Comparison and Identification
- 12: Gunshot Residue and Distance Determination
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
National Institute of Justice
The Research, Development, and Evaluation
Agency of the U.S. Department of Justice
Individual Characteristics
Home > Cartridge and Shotshell Examination > Identification > Individual Characteristics
The examination and identification of fired and unfired cartridge cases/shotshell cases are based on the following principles:
- The various parts of the operating mechanism of firearms (firing pin, breech face, chamber, extractor, ejector, and other areas) can bear unique microscopic characteristics as a result of manufacturing processes, use, and abuse.
- These characteristics may mark the surfaces of fired and unfired cartridge cases/shotshell cases with striated marks or impressions as they are fired in or cycled through the firearm.
- These individual characteristics may be reproducible and may be uniquely identifiable with a particular firearm.
These principles and the use of comparison microscopy combine to form the conceptual and physical foundation for firearm identification.
Click images below for larger image.
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Boltface and extractor)
Firing pin)
Chamber)
Extractor
