AFTE Store - The Use of Crimp Marks to Distinguish Between 357 SIG and 9mm Bullets

The author was presented with a case involving a fired, deformed, nominal 38 caliber, full metal jacketed bullet as evidence. It was important to the facts of the case to determine whether the bullet was 9mm Luger or 357 SIG caliber. While most of the discernable class characteristics of the questioned bullet were very similar to commonly produced bullets of both calibers, it was determined that the position of the cartridge case crimp mark relative to the base of the bullet could be used as a discriminating factor to help determine which of the two types of cartridges it had been fired from. Due to the longer case length of 357 SIG cartridges compared to 9mm Luger cartridges and the similar overall length of both cartridges, the corresponding cartridge case crimp mark on 357 SIG bullets will be located farther from the base than those on 9mm bullets. The research conducted in this case is discussed within the framework of the scientific method.