The shell casing is also marked by various parts of the firearm's internal mechanism:
To manage these vast amounts of data, law enforcement uses specialized databases and imaging systems. bullet fingerprinting
Unlike human fingerprints, a gun's "fingerprint" changes over time. Every shot fired slightly alters the microscopic striations in the barrel. Experts may only fire a limited number of test rounds because the fifth shot might already look different from the first. 2. Success Rates and "Expensive Failures" The shell casing is also marked by various
Barrel uniqueness in firearms: reliable forensic match? - Facebook bullet fingerprinting
: Microscopic flaws in the manufacturing process or wear and tear from use create a "signature" unique to that specific barrel. 2. Impression Marks (on the casing)
