What does the forensic firearms examiner look for in shell casings?
They look for the following: The indentation left by the firing pin: A simple visual inspection at the base of the shell casing reveals the location of where the firing pin hit, telling the forensic firearms examiner whether the shell had a primer cup, as seen in center-fire cartridges, or had a primer along the perimeter of the base, as seen in rim-fire cartridges. Knowing the location of where the firing pin hit can shorten the list of possible firearms used in a crime. Breechblock patterns: The breechblock refers to the back wall of the firing chamber. When gun powder within the casing explodes and violently forces the projectile down the barrel, the casing is pushed back against the breechblock, thus leaving an indentation on the bottom of the casing. Headstamps: Headstamps refer to the information stamped into the metal portion of cartridge casings and shotgun shells at the time they are manufactured. These markings sometimes include the factory’s initials or logo, the gauge or ca
