The new technique could lead to a stronger link between a suspect and a firearm, they said.
Researchers in Spain used spectroscopy to analyze six kinds of ammunition, assessing propellant from unfired cartridges then compared these spectra to the signature in residue from fired guns, ScienceNews.org reported.
The analysis revealed a particular residue signature for each type of ammunition, the researchers said.
U.S. scientists at the University of Albany in New York also employed spectroscopy to look for an ammunition signature in gunshot residue, comparing residue from a 9 mm and from a 0.38 special.
While the spectra looked similar, statistical analysis allowed the researchers to differentiate between the two calibers, they said.
The approach could be used to quickly rule out specific firearms found on a suspect or at a crime scene, researchers said.
"Anything that's going to enhance or expedite the detection of gunshot residue and provide stronger evidentiary value is a way forward," chemist Jason Birkett of Liverpool John Moores University in England said.
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