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For well over one hundred years the science of Firearm and Tool Mark Identification has
relied on the theory that unintentional random tooling marks generated during the
manufacture of a firearm onto its interior surfaces are unique to each individual
firearm.[1][2] Forensic Firearm and Tool Mark Examiners have had to rely on the analysis
of these randomly formed unintentional striations, or scratches and dings, transferred
onto ammunition components from firearms used to commit crimes, as a way of
developing clues and evidence. Such transfers take place during the cycle of fire and
ejection of the cartridge from the firearm during the commission of a crime.
The typical striations on the cartridge casings are caused by tooling marks that are
randomly formed during the machining of interior surfaces of the manufactured firearm
and by other firearm components that come in contact with the cycling ammunition.
Components like the firing pin, extractor and ejector, impact the surfaces of the cartridges
as they are fed, fired and ejected from the firearm. When found at a crime scene, these
striae constitute ballistic evidence when effectively analyzed by a Forensic Firearm and
Tool Mark Examiner. Examiners categorize these striations looking for matches to be
made between the components that created the marks and the recovered firearm. Reality
is that nearly 50% of firearms used in violent crimes are not recovered at a crime scene,
requiring the analysis to be processed and logged into evidence files or imaged into
reference image databases for future comparison whenever a firearm might be recovered.
This paper will present a unique law enforcement technology, embedded into firearms for
tracking the sources of illegally trafficked firearms, called Microstamping.
Microstamping is a laser based micromachining process that forms microscopic
"intentional structures and marks" on components within a firearm. Thus when the
firearm is fired, these microstamp structures transfer an identifying tracking code onto the
expended cartridge ejected from the firearm. Microstamped structures are laser
micromachined alpha numeric and encoded geometric tracking numbers, linked to the
serial number of the firearm.
Ballistic testing data will be presented covering microstamp transfer quality, transfer rates
and survivability/durability. Further information will provide an overview on how microstamping information can be utilized by law enforcement to combat illegal firearm
trafficking.
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