What is a conclusion that a firearms examiner can render if striations do not match?

A firearms examiner analyzes bullets and cartridge cases to determine their origin. When striations, which are unique markings left on a bullet by the gun's lands and grooves, do not match, it can lead to specific conclusions about the firearm involved.

In this context, if striations do not match, and class characteristics (the general shape and design features shared by firearms of the same model) also do not match, it can be concluded that the suspect gun is excluded from having fired that bullet. This conclusion is based on the principle that each firearm produces unique striations due to wear and manufacturing differences; therefore, a lack of matching striations means that it is not possible for the bullet to have been fired from the suspect firearm.

This conclusion is critical in forensic investigations as it aids in narrowing down potential weapons and ultimately contributes to the overall evidence that may lead to identifying the actual firearm used in a crime.