What is Gunshot residue?
'''Gunshot residue''' (GSR) is one of the results of firing a [[gun]]. When a [[bullet]] leaves the [[barrel (weapons)|barrel]] of a [[firearm]], it is accompanied by [[gas]]es that include both burned and unburned [[particle]]s of [[gunpowder]]. It also includes traces of [[metal]] from the firearm, the [[ammunition]] and the [[primer (firearm)|primer]] including the signature components of gunshot residue: [[lead]], [[barium]] and [[antimony]].<ref>{{cite web |url=http://www.forensicmag.com/articles/2012/09/science-behind-gsr-separating-fact-fiction |title=The Science Behind GSR: Separating Fact from Fiction |author=Allison C. MurthaLinxian Wu |date=27 September 2012 |publisher=Forensic Magazine |access-date=20 January 2016 |archive-date=6 December 2015 |archive-url=https://web.archive.org/web/20151206174423/http://www.forensicmag.com/articles/2012/09/science-behind-gsr-separating-fact-fiction |url-status=dead }}</ref> GSR is usually found on the [[skin]] and [[clothing]] of the person who fired the gun.<ref name=Eccles>{{cite web |url=http://library.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNGSR.html |title=Examination of Gunshot Residue |publisher=The University of Utah, Spencer S. Eccles Health Sciences Library |access-date=20 January 2016}}</ref> It may also be found in the entrance [[wound]] of the [[victim]].<ref name=MDPS>{{cite web |url=https://dps.mn.gov/divisions/bca/bca-divisions/forensic-science/Pages/forensic-programs-crime-scene-gsr.aspx |title=Gunshot Residue Collection |publisher=Minnesota Department of Public Safety |access-date=20 January 2016 |archive-date=2 November 2020 |archive-url=https://web.archive.org/web/20201102232639/https://dps.mn.gov/divisions/bca/bca-divisions/forensic-science/Pages/forensic-programs-crime-scene-gsr.aspx |url-status=dead }}</ref> This depends on how close the victim was to the gun when it was fired. == Forensic science of GSR == When a gun is fired, a [[wikt:plume|plume]] of gas—including GSR particles—is ejected from the barrel and any other openings in the gun.<ref