FIGURE 3-1 Overview of development of Prather clay methodology. Stage 1: depth correlation of goats with gelatin in soft body armor. Stage 2: injury assessment with rigid impactor onto goats, gelatin, and clay. SOURCE: Prather et al., 1977.
In the 1970s, 80 percent of the civilian handgun threat comprised .38-caliber and smaller handgun rounds. The primary rounds chosen for this program were the .38-cal, 158-grain lead round nose (LRN) bullet with initial velocity of 244 m/sec (800 ft/sec) and the .22-cal, 40-grain long rifle high-velocity bullet with an initial velocity of 305 m/sec (1,000 ft/sec). The garments developed under this program had to be lightweight, inconspicuous, and wearable. Additional requirements included protection from bullet penetration, blunt trauma mortality risk of less than 10 percent, and sufficient protection to allow the wearer to walk away from any shooting incident. Note that these last two requirements are not necessarily contradictory, because overall mortality risk might involve