Date of Submission

5-12-2026

Document Type

Thesis

Department

Forensic Science

Advisor

Virginia M. Maxwell, D. Phil.

Keywords

9mm Luger, Fired Cartridge Cases, Class Characteristics, Quantitative Variance, Probative Value

LCSH

Luger pistol, Firearms, Forensic ballistics

Abstract

This study analyzes the variation of class characteristics in fired cartridge cases from firearms that use the 9mm Luger ammunition and evaluate how laboratories should make conclusions on this kind of evidence. The research uses 10 different firearms and each discharging 50 rounds of ammunition. These samples were examined for quantitative data regarding position and size among fired cartridge cases. Comparisons were made between cartridge cases fired by different weapons as well as between the same weapon before and after a series of rounds. In this experiment, it was found that all class characteristics showed some form of quantitative variance. For characteristics such as length, height, and left-right distance of firing pin, the variance was found to be minimal. This variation is negligible and would consider the cartridges under the same class characteristic. The length of firing pin drag had shown a larger variation of measurements which, in some samples, result in a different categorical characteristic entirely. Therefore, based on the findings of these experiments, the varying probative value of different class characteristics within a cartridge case should be considered when examiners use it for exclusionary purposes. In addition, laboratories should consider a variety of conditions rather than making one-to-one comparisons of questioned and a singular known cartridge, or several cartridges with a low range of conditions.

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Available for download on Thursday, May 13, 2027

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