NCJ Number
215683
Journal
Journal of Forensic Identification Volume: 56 Issue: 5 Dated: September-October 2006 Pages: 721-725
Date Published
September 2006
Length
5 pages
Annotation
This study surveyed and plotted cartridge-casing ejection patterns from two types of 9 mm self-loading pistols (Glock 17 and Sig Sauer P226).
Abstract
Both guns produced a grouping of cartridge casings to the rear and right of the shooter; however, the Glock produced a more linear spread of cartridge casings compared to the Sig Sauer. The main difference between the cartridge ejection patterns of the two guns was the trendline. The Glock produced an angular trendline from the direction of shooting, and the Sig Sauer produced a trendline that was more parallel to the direction of shooting. Variables that may influence the final ejection patterns include height and grip of the shooter; internal wear within the firearm; yaw, pitch, and roll of the firearm as it is being fired; differing powers of the ammunition; surface on which the cartridge casing lands; prevailing weather conditions; and external interference in the casework. These factors should be examined in further research and casework. Both of the firearms used were well-maintained police-issued weapons. The shooter in the testing was a police firearms instructor, who held the weapon in his right hand supported by his left hand, using the Weaver stance. An indoor range was used to reduce the effects that weather might have on the ejection patterns. The cartridge casings were ejected onto sand to reduce their bounce and roll. The ejection patterns were surveyed by using a Sokkia Set 5W/5WS Total Station and an optical target, so as to allow the accurate plotting of the 50 cartridge casings from the testing. 3 figures and 4 references