AFTE Store - Toolmark Reproducibility on Fired Bullets and Expended Cartridge Cases

The reproducibility of landmarks, breechface marks and firing pin marks on one hundred successively fired bullets and cartridge cases was examined. Three types of Speer brand, one of Remington brand and one of DFA brand frangible cartridges were fired in a semi-automatic pistol. Remarkable differences were observed in the general appearance of the landmarks, breechface marks and firing pin marks which were impressed on the different brands of cartridges, even when consecutively fired. Identification of the landmarks between bullets from different brands of cartridges was difficult because their general appearance differed greatly. Difference in bullet diameters was found to be a major cause of changes in landmarks among different manufacturer’s bullets. Although the depth and number of striations decreased gradually, reproducibility of breechface marks on the primers of cartridges was rather good. The diameter of firing pin indentations also differed among different brands of cartridges. Although the reproducibility of the diameter of circular lines on firing pin indentations was good, the detail in these circular lines fluctuated a great deal. Quantitative CMS was used as a means of critically evaluating and communicating the extent of striated pattern agreement among the rifling impressions on the fired bullets in this study.

Full Journal: AFTE Journal Vol 40 No 1 (2008)