AFTE Store - Firing Pin Rotation and its Effect on Cartridge Case Identification Systems

With the widespread use of computer aided cartridge case identification systems, I,e, Drugfire and IBIS (NIBIN), the firing pin impression has become an important piece of information. Distinguishing marks on the firing pin may he the bridge that links one or more unsolved cases. The examiner needs to be cautioned that he or she can inadvertently overlook these marks if the mark moves to another location in the impression due to the rotation of the firing pin. This is not true for all firearms, so in order to determine which semiautomatic weapons contain tiring pins that rotate, a study was conducted using the Miami-Dade Police Department Crime Laboratory firearms reference collection. The following calibers were selected to determine their propensity to rotate: 9mm, .380, .223, 7.62 x 39mm, 7.62 x 51mm.