A Computerized Database for Bullet Comparison by Consecutive Matching
Ashley Chu, David Read, David Howitt
ABSTRACT
A method for cataloguing and comparing the land impressions of bullets using readily available commercial instrumentation and software is described. The analysis involved a comparison of the locations of the prominent features of the land impression topography in much the same way that firearms examiners in California use consecutive matching striae except they were determined from the reconstruction of the surfaces by confocal microscopy. The database that was used to test the method contained 1686 land impressions fired from Beretta M9/92 pistols and was supplemented with additional random-simulated data to a total of 90,000 bullets. 232 of the 281 scanned bullets were duplicate firings, that is there were pairs of bullets fired from 116 guns and without excluding any bullets because of the quality of the impression marks over 60% of the duplicate firings were identified before a false positive match occurred.