Smalls arms propellants (SAP) are readily accessible and cost-effective materials that firearms enthusiasts can acquire for the legitimate assembly of ammunition. Unfortunately, the ease of access and low cost of these materials is advantageous for their utilization in the construction of improvised explosive devices (IEDs). Typically, the SAP charge is loaded into a metal pipe (commonly steel) and sealed with screw-fit end caps. These devices are termed “pipe bombs” and are the most common IEDs in the United States. Two recent high profile domestic terrorist attacks using IEDs (Boston Marathon Bombing and NY/NJ attempted bombings) further demonstrate their continued usage. Thus, there is a need to develop robust metrics for the characterization of propellants that are used as explosives as well as for comparisons between known and recovered explosive residues. The goals of the research are to investigate the utility of high-throughput, low-cost quantitative automated image analysis, additive profiling and compound-specific stable isotope signatures of SAP for potential brand identification and sample discrimination. If found to be successful, the metrics will provide advanced methods for the examination of small arms propellants recovered from pre- and post-blast improvised explosive devices. The automated image analysis method is appealing since it is non-destructive and relies upon low-cost analytical equipment and instrumentation. A rigorous assessment of the existing GC/MS additive profiling methodology will be achieved as well as a better understanding of its role in SAP examination. The measurement of compound-specific stable isotope signatures is considered a final tier analysis, which may provide highly discriminatory information that could constrain geographic/ manufacturer-specific characteristics. The research is the first of its kind to combine uncorrelated data sets from complementary analytical methods for the characterization of SAP in forensic and intelligence casework. (Author summary provided.)
Assessing automated image analysis and compound-specific stable isotope signatures for small arms propellant differentiation and potential brand identification
NCJ Number
310703
Date Published
September 2025
Length
30 pages
Abstract
Date Published: September 1, 2025