By Thomas Fadul, Laboratory Manager, Forensic Identification Section, Miami-Dade Police Crime Laboratory,
n the early 1990s several shootings involving Miami, Florida, Police Department officers using Glock firearms received widespread media attention. It also revealed the Glock weapons’ identification problem.
Glock is one of a few manufacturers that use a polygonal rifled barrel. Due to this particular manufacturing process, in most cases the weapon failed to leave an identifiable signature.
Originially, Glock responded to this concern by developing a technique known as the Electronic Spark Reduction Method (ESRM).1 However, an in-depth study by the Miami-Dade, Florida, Police Department (MDPD) Crime Laboratory Bureau (CLB) found that Glock’s ESRM failed to make the firearm easier to identify.
Not until 2001, after a suspect was killed during a shooting involving three officers and the examiners were unable to positively identify which officer had fired the fatal shot, did Glock develop a barrel that left a unique signature on the bullet.
In 2003, Glock introduced the Enhanced Bullet Identification System that has become known as the “Miami Barrel.” Now an extensive study, spearheaded by the MDPD CLB, is being conducted in more than 120 crime labs across 41 states to determine the effectiveness and identifiability of the Miami Barrel. Several smaller research studies have been conducted since the barrel was first introduced, but this new study aims to provide the in-depth data required by police agencies nationwide regarding Glock weapons’ use and identification.
Development of the Miami Barrel
|Caption: Comparison of two bullets fired|
through Glock’s “EBIS” (Miami) barrel.
Deep grooves identify it as the Glock
EBIS; shallow grooves identify it to
the specific barrel.
Photo courtesy of Crime Laboratory
Bureau, Miami-Dade Police Department
In 2002, after several attempts that were deemed “not readily identifiable,”2 Glock’s chief engineer Reinhold Hirschheiter met with members of the MDPD CLB to discuss refining their marking system. The team advised Hirschheiter that the cuts being made needed to be deeper and thicker and needed to consistently score the bullets at their circumference.
In 2003, the MDPD CLB received three new modified Glock barrels. Bore examination of the three barrels found a series of randomly spaced fine lines with the same direction as the polygonal rifling. Initial test comparisons of the three barrels found significant transfer of gross marks on fired bullets—possible subclass characteristics from the barrels—yet careful examination rendered the barrels distinct and “readily identifiable.”
Similar gross characteristics made from the deeper cuts repeated on several land impressions on test bullets from the same barrel. These gross characteristics also repeated from barrel to barrel. Although visually similar in overall width and depth, these gross characteristics were distinguished at higher powers of magnification (for example, 25X), which also aided in visualizing the fine individual characteristics imparted in the land impressions.
A total of 3,000 rounds were fired through the new barrels for durability testing. Test bullets from the barrels were microscopically compared after 3,000 rounds. Even though test bullets from both barrels possessed some similar gross characteristics, they were still distinguishable from each other. The similarities in gross characteristics were no longer as pronounced, but nevertheless aided in indexing and identifying tests from the same barrel.
Even though the findings suggested that gross (possible subclass) characteristics on consecutive land impressions will appear differently as compared to an area of similarity on a bullet from a different barrel, it was still possible that multiple lands from one barrel might have similar gross characteristics as lands from another barrel because the subclass has an appearance of a barcode (the same pattern of barcode could repeat from barrel to barrel).
In producing large numbers of barrels, the manufacturing techniques used to individualize these new barrels may result in some barrels that are very difficult to differentiate. Lengthy time periods between the incident and recovery of the weapon may increase the changes in gross characteristics remaining on the land impressions but, based on the durability study conducted by the MDPD, these factors should not hinder positive identifications.
Examiner Experience Is Key
An examiner with knowledge of the machining methods and awareness of the possible subclass transfer and diminishing quality of these gross markings over time should still appropriately arrive at positive identifications. The individual characteristics persisted after 3,000 rounds, and the bullets were readily identifiable. Of greater concern, may be an examiner who is unfamiliar with these markings and who relies on the gross characteristics alone for a positive identification.
Although the MDPD CLB was able to correctly identify the bullets fired from the above barrels, additional questions arose regarding consecutively manufactured barrels.
In 2007, Judy Chin and Benjamin Sampson performed a blind study utilizing four Miami/EBIS Barrels. They concluded that the questioned bullets and known standards (test-fired bullets) were correctly identified.3 They were concerned that different barrels could have the same subclass characteristics that could be mistaken for individual characteristics by an uninformed examiner; Thomas Fadul Jr. and Adrian Nunez had had the same concern in 2006.4
In 2008, Carolyn Martinez conducted a durability study utilizing the Miami/EBIS Barrel. The Martinez study5 reported that 29 percent of the participants with five to 10 years of experience reported via survey testing that there were not enough individual characteristics present to conclude an identification and/or elimination. Additionally, 14 percent of the participants with five to 10 years of experience reported identifications and the ability to eliminate. Martinez believed that the identifications were made using the process of elimination. This study’s outcome may have been due to a lack of training with the Miami/EBIS Barrel.
Enhanced Testing of the Enhanced Bullet ID System
For this latest 2009 study, the MDPD CLB obtained 10 consecutively manufactured Glock Miami/EBIS Barrels to further explore the capability of identifying bullets fired through the Glock Miami/EBIS Barrels. On a voluntary basis, 120 test sets were created and distributed to laboratories in 41 states.
The test set was designed to determine an examiner’s ability to correctly identify bullets fired from 10 consecutively manufactured Miami Barrels (EBIS Barrels) to test-fired bullets fired from the same barrels. Each test set consists of two test-fired bullets from each of the 10 Miami Barrels (EBIS Barrels) marked with the barrel number, and 15 fired bullets marked with alpha characters that need to be identified. The results from this new extensive study will be published upon its completion, which could be published as early as winter 2009. ■
1J. Carr and Thomas Fadul, “The Miami Barrel,” AFTE Journal 29, no.2 (1997): 232–233.
2Thomas G. Fadul Jr. and Adrian Nunez, “The Miami Barrel Saga Continues,” AFTE Journal 35, no.3 (2003): 290–297.
3Judy Chin and Benjamin Sampson, “Glock Enhanced Bullet Identification System (EBIS) Barrels” (paper presented at the meeting of the Association of Firearm and Tool Mark Examiners Annual Training Seminar, San Francisco, California, May 2007).
4Thomas G. Fadul Jr. and Adrian Nunez, “Glock’s New EBIS Barrel: The Finale to the Miami Barrel,” AFTE Journal 38, no. 2 (2006): 96–100.
5Carolyn Martinez, “Glock’s Signature Barrel—Durability of the EBIS Markings” (paper, the Association of Firearm and Tool Mark Examiners Annual Training Seminar, Honolulu, Hawaii, May 2008).