Wounding Patterns Based on Firearm Type in Civilian Public Mass Shootings in the United States

There are no studies correlating wounding pattern or probability of death based on firearm type used in civilian public mass shooting (CPMS) events. Previous studies on non-CPMS events found that handguns are more lethal than rifles. We hypothesized that CPMS events associated with a handgun are also more lethal than those associated with a rifle.

A retrospective study of autopsy reports from CPMS events was performed; CPMS was defined using the FBI and the Congressional Research Service definition. Site(s) of injury, site(s) of fatal injury, and presence of potentially preventable death (PPD) were determined independently by each author and cross-referenced to firearm type used.

Autopsy reports of 232 victims from 23 events were reviewed. Seventy-three victims (31%) were shot by handguns, 105 (45%) by rifles, 22 (9%) by shotguns, and 32 (14%) by multiple firearms. Events using a handgun were associated with a higher percentage killed, and events using a rifle were associated with more people shot, although neither difference reached statistical significance. Victims shot by handguns had the highest percentage of having more than 1 fatal wound (26%); those shot by rifle had the lowest percentage (2%) (p = 0.003). Thirty-eight victims (16%) were judged to have had a PPD. The probability of having a PPD was lowest for events involving a handgun (4%) and highest for events involving a rifle (23%) (p = 0.002). Wounding with a handgun was significantly associated with brain (p = 0.007) and cardiac injury (p = 0.03).

Civilian public mass shooting events with a handgun are more lethal than those associated with use of a rifle.