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Empirical Study to Improve the Scientific Foundation of Forensic Firearm and Tool Mark Identification Utilizing Consecutively Manufactured Glock EBIS Barrels

NCJ Number
Date Published
December 2013
51 pages
This study assessed the reproducibility and uniqueness of striations imparted by consecutively manufactured Glock Enhanced Bullet Identification System (EBIS) barrels with the same EBIS pattern, and determined the error rate for the identification of same-gun evidence.
The research findings indicate that firearm and tool-mark examiners demonstrated a very low error rate (0.007) when comparing bullets fired in consecutively manufactured barrels. Further, the findings show that a trained firearm and tool mark examiner with 2 years of training, regardless of experience, will correctly identify same-gun evidence. This research addressed concerns that were raised by the 2009 National Academy of Science Report entitled, "Strengthening Forensic Science in the United States: A Path Forward." This report questioned the repeatability and uniqueness of striations left on fired evidence used to identify same-gun evidence and also questioned the error rate of firearms identification. Consecutively manufactured barrels represent the best possibility for the production of two firearms that could produce indistinguishable markings, since the same tools and machining processes are used back-to-back on one barrel after another. This process thus represents a situation in which the most similarity is likely to occur between two separately manufactured barrels. The manufacturing process of EBIS barrels is described in detail, and the strengths and weaknesses of the internal and external validity of the research design and implementation are outlined. A total of 165 accredited members of the Association of Firearm and Tool Mark Examiners (AFTE) who had at least 2 years of training, regardless of experience, were selected through a nationwide survey. The credentials of the statistical analyst and the statistical method are reported. 4 tables, 38 references, and appended study instruments

Date Published: December 1, 2013