Movement of the firearm during firing createda very different pattern of spent cartridge
casings. Again restricting the study of the distribution pattern to the cartridges ejected from the
Glock 17, we found the distribution as shown in Figure 10. This figure represents test eight and
illustrates spent cartridge casings ejected from a firearm held with a two-handed grip, pointed
downwards 22 degrees, and the shooter going through a 45 degree body rotation with his/her
weapon. Spent cartridge casings landed in all but one 30-degree section. Nearly 30 % landed to
the left and rear of the shooter. This was very different from test one with the same semiautomatic weapon. From this test, weapon motion isevident to have contributed to the location
of spent cartridge casings asthe reader can see from comparing Figure 8 with Figure 10.
The spent cartridge casing locations shown inFigure 10 are found in a 360-degree circle
about the shooter illustrating the impact of firearm motion on the exact location of spent
cartridge casings. Variability within quadrants is also impacted by firearm motion as the reader
can see in the distances traveled by the spent cartridge casings; 7.21 inches (18.31 cm) to 143.13
inches (363.55 cm) away from the zero point. This gave an average distance of 44.43 inches
(112.85 cm) from the shooter or a difference of over 8 feet (2.44 m) from the maximum distance.
As noted elsewhere the pilot studies where the shooters were able to hold the firearm in the test
position and shoot at a target while they were moving rapidly produced a much greater scatter of
spent cartridge casing to the left ofthe shooter than was obtained here.