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Gunshot residue (GSR), also known as cartridge discharge residue (CDR), "gunfire residue"(GFR), or firearm discharge residue (FDR), is residue deposited on the hands and clothes of someone who discharges a firearm. It is principally composed of burnt and unburnt particles from the explosive primer, the propellant—and possibly fragments of the bullet, cartridge case, and the firearm. Law enforcement investigators test the clothing and skin of people for GSR to determine if they were near a gun when it discharged. Gunshot residue can travel over 3–5 feet (0.9–1.5 meters) from the gun. At the farthest distance, only a few trace particles may be present. ==History== In 1971 John Boehm presented some micrographs of GSR particles found during the examination of bullet entrance holes using a scanning electron microscope. If the scanning electron microscope is equipped with an energy-dispersive X-ray spectroscopy detector, the chemical elements present in such particles, mainly lead, antimony and barium, can be identified. In 1979 Wolten et al. proposed a classification of GSR based on composition, morphology, and size. Four compositions were considered ''characteristic'': * Lead, antimony, and barium * Barium, calcium, and silicon * Antimony * Barium. The authors proposed some rules about chemical elements that could also be present in these particles. Wallace and McQuillan published a new classification of the GSR particles in 1984. They labeled as ''unique'' particles those that contain lead, antimony, and barium, or that contain antimony and barium. Wallace and McQuillan also maintained that these particles could contain only some chemical elements. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gunshot residue」の詳細全文を読む スポンサード リンク
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