Defense Date
2026
Document Type
Directed Research Project
First Advisor
Stephanie Walcott
Second Advisor
Eric Hazelrigg
Third Advisor
Rosemary Harton
Abstract
The determination of muzzle-to-target distance remains a significant challenge in forensic casework. Current approaches to gunshot residue (GSR) analysis rely primarily on colorimetric testing to indicate chemical components present and subjective interpretation, limiting specificity and contributing to ongoing scrutiny within the field. This study investigates a quantitative method for estimating shooting distance based on the concentration of lead present in GSR samples (w/w%) with the utilization of inductively coupled plasma optical emission spectrometry (ICP-OES). Test firings were conducted using caliber 22 Long Rifle, 9mm Luger, and 40 S&W semiautomatic handguns at defined distances to evaluate the relationship between lead concentration and muzzle-to-target distance. Statistical analyses were performed to assess the discriminatory power and specificity of the method across calibers. Results demonstrate a measurable correlation between lead concentration and distance, supporting the potential for quantitative distance estimation. However, variability in GSR production necessitates the availability of the suspect firearm and corresponding ammunition for accurate application. Further validation is required to establish robustness and reproducibility for forensic implementation.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
4-30-2026