Since all the data obtained from this study is too large to fit in this article the authors have
chosen to present specific results in a broad to precise fashion. Significant variables such as
firearm position, motion, grip, weapon type, and ammunition will be taken into consideration
one-by-one. This one-by-one approach is to illustrate the impact of each individual variable on
the spent cartridge casing patterns. First, all 7,670 spent cartridge casing locations will be
presented without any other variables being considered. Next, insection two, the impact of
firearm position and grip alone will be illustrated while firearm type, ammunition, and weapon
motion will be left as an unknown. Then in section three weapon type results will be illustrated,
followed by section four, which isfirearm motion and finally section five, ammunition type. This
is to help demonstrate how unpredictable spent cartridge casing locations are when several
variables are not accounted for and are still unpredictable even when these variables are
accounted for. The authors’ goal in this way ofpresenting the results is to illustrate how
imprecise determining shooter’s location is even when several important variables are known
and accounted for and not just when variables are unknown.
Further statistical analysis of the tests presented below is contained ina table located after
each of the scatter plots. This information is presented in two sections within a single table so
that the reader can see both the angles, in degrees, in which the spent cartridge casings flew after
being ejected from the weapon and the distance, in inches (and cm), that they traveled from the
shooter. First the mean (average), standard deviation, median (the middle number), and mode (most common number) are given for the angles (degrees) in which the spent cartridge casings
flew from the center point where each participant fired his/her firearm. A negative number from
0 to 90 signals the spent cartridge casing flew behind and to the right of the participant; a
negative number from 91 to 180 signals the spent cartridge casing flew behind and to the left of
the participant. A positive number from 0 to 90 is to the front and right of the participant and 91
to 180 is to the front and left of the participant. Secondly, the mean, standard deviation, median,
and mode of the spent cartridge casings for that specific test are given in inches (cm) for each
individual quadrant, described above. This tells the reader how far in inches (cm) the spent
cartridge casings landed from the center point in any direction. These tables are to help the
reader understand more specific areas in which the spent cartridge casings landed for each of the
individual tests illustrated below.