Background

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                                                                             Background

A deeper dive into its meaning is necessary to provide further background information on fired cartridge casing analysis. Beginning with what is currently known about the subject. When a bullet is fired from a gun, the spent shell casing that the bullet leaves behind is always left with very distinctive markings. It is not uncommon to relate specific markings to that human fingerprints. When a gun fires a particular bullet, it leaves behind markings, scorching, and indentations that can be traced back to a particular gun, manufacturer, and bullet caliber. In the article “SRM 2460/2461 standard bullets and casings project,” Song explains: “Bullets and casings when fired or ejected from guns, pick up characteristic signatures, which are unique to the weapon. Striations on the bullet are caused by its passage through the gun barrel. Marks on the casing are caused by impact with the firing pin, breech face and ejector” (Song, et al.). Once a pattern of specific markings is established, these can all be documented and used as a comparative control within examinations, similar to fingerprints. 

This is a critically important tool when solving potential crimes because it can provide a pinpoint, accurate method to trace a particular bullet, gun, and manufacturer of both items back to a crime scene. In a way, this can almost be seen as the “DNA” of a gun that can be vital in making or breaking a criminal case. To reiterate, my research question is: With careful analysis, can class characteristics on a fired cartridge casing be significant enough to identify a specific gun that fired it? My revised hypothesis on the subject is: We will be able to determine if there is significant evidence to identify which casing was shot from a specific gun by comparing class characteristics.


Here is a side-by-side comparison of the same casing just rotated counter-clockwise 90 degrees.






References

Cork, D. L., Nair, V. N., & Rolph, J. E. (2010). Some forensic aspects of ballistic imaging. Fordham Urban Law Journal, 38(2), 473+. https://link.gale.com/apps/doc/A250885610/AONE?u=mcc_phoe&sid=summon&xid=dae2a1b9

Dong, F., Zhao, Y., Luo, Y., Zhang, W., & Zhang, K. (2019). Specificity of characteristic marks on cartridge cases from 3070 consecutive firings of a Chinese Norinco QSZ-92 9 mm Pistol. Journal of Forensic Science and Medicine, 5(2), 87. https://link.gale.com/apps/doc/A592117545/SCIC?u=mcc_phoe&sid=bookmark-SCIC&xid=6797e8dc

Kara, I., & Karatatar, A. (2022). Classification of fired cartridge cases using 3D image capture and a comparison of database correlation method performance. Journal of Forensic Sciences, 67(5), 1998-2008. https://doi.org/10.1111/1556-4029.15089

Kirk, J. (2015). Estimation of changes in breech face and firing pin marks over consecutive discharges and its impact on 2D correlation systems (Order No. 1588089). Available from Criminal Justice Database. (1682044732). https://ezproxy.pc.maricopa.edu/login?url=https://www-proquest-com.ezproxy.pc.maricopa.edu/dissertations-theses/estimation-changes-breech-face-firing-pin-marks/docview/1682044732/se-2

Passalacqua, P., Pallocci, M., De Luca, L., Zanovello, C., Sacchetti, G., & Treglia, M. (2022). Tandem bullets: case report and ballistic analysis. Egyptian Journal of Forensic Sciences, 12(1)https://doi-org.ezproxy.pc.maricopa.edu/10.1186/s41935-022-00297-z

Tobin, W. A., & Blau, P. J. (2013). HYPOTHESIS TESTING OF THE CRITICAL UNDERLYING PREMISE OF DISCERNIBLE UNIQUENESS IN FIREARMS-TOOLMARKS FORENSIC PRACTICE. Jurimetrics, 53(2), 121-142. https://ezproxy.pc.maricopa.edu/login?url=https://www-proquest-com.ezproxy.pc.maricopa.edu/scholarly-journals/hypothesis-testing-critical-underlying-premise/docview/1428261921/se-2

Scicchitano, K. M. (2011). The Effect of Examiner Variation in Cartridge Case Acquisition on IBISreg Correlation Scores and the Ability of the System to Return a True Positive (Order No. 1501718). Available from Criminal Justice Database. (894254147). https://ezproxy.pc.maricopa.edu/login?url=https://www-proquest-com.ezproxy.pc.maricopa.edu/dissertations-theses/effect-examiner-variation-cartridge-case/docview/894254147/se-2

Song, J., Whitenton, E., Kelley, D., Clary, R., Ma, L., Ballou, S., & Ols M. (2004). SRM 2460/2461 standard bullets and casings project. Journal of Research of the National Institute of Standards and Technology, 109(6), 533+. https://link.gale.com/apps/doc/A130348255/SCIC?u=mcc_phoe&sid=bookmark-SCIC&xid=c58a90f6

Tong, M., Song, J., Chu, W., & Thompson, R. M. (2014). Fired cartridge case identification using optical images and the Congruent Matching Cells (CMC) method. Journal of Research of the National Institute of Standards and Technology, 119(1), 575+. https://link.gale.com/apps/doc/A419149636/SCIC?u=mcc_phoe&sid=bookmark-SCIC&xid=3529b3f5

Vorburger, T. V., Yen, J., Song, J. F., Thompson, R. M., Renegar, T. B., Zheng, A., & Tong, M. (2014). The second National Ballistics Imaging Comparison (NBIC-2). Journal of Research of the National Institute of Standards and Technology, 119(1), 644+. https://link.gale.com/apps/doc/A419149641/SCIC?u=mcc_phoe&sid=bookmark-SCIC&xid=6e1e2d65

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