Physical Examination of Fired Cartridge Cases

When a firearm is discharged, the cartridge case comes in contact with the firing pin, the breech face, the extractor, the ejector and the chamber. A negative profile of the surface of the firearm parts coming in contact with the surfaces of the fired cartridge case is imprinted. This thumbprint of the firearm permits the individualization of the firearm. Therefore, it is very necessary for a cartridge case to be properly physically examined first. For physical examination of the cartridge case a proper procedure should be followed so that all individual markings can be deciphered easily under the comparison microscope.