most spent cartridge cases land to the rightand rear of the
shooter. The authors of this study investigated whether spent cartridge case
ejection locations are an accurate indicator of a shooter’s location. Eight different
semi-automatic weapons most frequentlyused by police officers were used to
collect data from eleven different shooting positions. The results highlighted the
significant inconsistency ofthe spent cartridge case ejection locations that
occurred across test positions even whenseveral factors including firearm type,
firearm position, and ammunition were accounted for. Of 7,670 bullets fired, over
25 percent of the spent cartridge casings landed somewhere other than to the right
and rear of the shooter where it iscommonly accepted they should land. That
pattern inconsistency is significant and demonstrates that determining shooter
location from the spent cartridge case aloneleads to only a tentative estimate of
the shooter’s location.