Every firearm leaves unique, reproducible markings on expended bullet and cartridge cases that it fired. The barrel,
firing pin, firing chamber, extractor, ejector and other parts of the gun leave these marks, called tool marks, on the
bullet and cartridge case faces. Individually and collectively, these markings function as the “ballistic signature” of
Automated Firearms Identification System (AFIS) are specialized computer hardware/soƜware combinations
designed to capture, store and rapidly compare digital images of bullets and cartridge casings.
Law enforcement agencies worldwide utilize AFIS to rapidly generate Candidate Lists of probable matches of a
suspect bullet/cartridge against the ballistic database. Depending on the agency’s requirements, AFIS will generate
the Top 10, Top 20, etc. list of probable matches. The Firearms Examiners then use these candidate lists to select the
actual bullets/cartridges they will visually compare with the suspect bullet/cartridge.