**Researchers: Forensic science method for firearm identification is flawed**

Like fingerprints, a firearm's discarded shell casings have unique markings. This allows forensic experts to compare casings from a crime scene with those from a suspect's gun. Finding and reporting a mismatch can help free the innocent, just as a match can incriminate the guilty.

https://phys.org/news/2023-10-forensic-science-method-firearm-identification.html