AFTE Store - The Significance of Bunter Toolmark Association in a Limited Geographic Area

At times, examiners are asked to compare cartridge cases from a crime scene to cartridges found in a suspect’s possession to determine whether or not the headstamps were produced by the same bunter tool. Previous research demonstrated that bunter toolmarks, which are transferred to each headstamp, are unique and persist over some portion of a production run. This study examined the significance of bunter toolmarks through the examination of caliber 9mm Luger ammunition from the Federal Cartridge Company, purchased in a limited time period within the Commonwealth of Virginia. Results indicate that at least two different bunter tools were found to be represented in a box of ammunition. Within a box, a bunter tool may be represented by only one or two cartridges. Boxes from the same lot often contain common bunter toolmarks. However, identical bunter toolmarks were found in ammunition boxes of different lot numbers. In addition, identical bunter toolmarks were found in boxes of ammunition purchased in different geographic regions. This study indicates that bunter toolmark examinations do not provide valuable information associating or disassociating evidence cartridge cases and cartridges from a suspect’s possession.