When a bullet is fired from a gun, the barrel leaves distinctive scratch marks on the surface of the bullet. These microscopic marks are highly similar for bullets fired from the same gun, meaning they can be used for forensic comparison, matching bullets taken from a crime scene to a particular gun. However, crime-scene bullets are often deformed from collisions, which can make direct comparison difficult. Now, NIST researchers have developed a new algorithm that makes this matching more accurate, by dividing the markings on the deformed bullets into segments, and correlating those segments with the reference bullet.
