Brass Fetcher Ballistic Testing
The first recorded Personal Defense Weapon was the German Luger, issued with a shoulder stock, in World War I. Accompanying the astonishingly rapid advances made during that era in military hardware came an increasing tendency among planners to make warfare a ‘game of numbers.’ Specifically, the application of statistics and probability to small arms design and conceptualization began in its infancy during this time period.
Personal Defense Weapons, PDWs, are intended to be used by personnel whose role does not make them likely to need a firearm with any great frequency. Such firearms are lightweight, small in size and hold a large number of cartridges. They differ from submachineguns in that PDWs typically offer lower recoil (and often lower terminal effectiveness against a human attacker), greater armor piercing capability (with ammunition designed to penetrate soft body armor) and better controllability during fully automatic fire. Modern implementations of this concept include the Heckler & Koch MP7 and the FN P90.
High-velocity projectiles such as bullets have two distinct wounding mechanisms: tumbling and expansion. Military rifle bullets will tumble after traveling some distance into the gelatin block or the body of a human attacker. The wounding can be dramatic if the tumble comes quickly enough. Jacketed hollowpoints intended for use in handguns will expand within the first two diameters of penetration and will rapidly decelerate within the target. This is what is desired when engaging structures of the body that offer narrow shotlines such as hits to the arms and legs. In order to be effective a Jacketed Hollowpoint must be capable of expanding and penetrating deep into the chest cavity as well. If any expansion takes place, this necessitates firing a cartridge in the 9mm Luger or larger kinetic energy ‘ballpark.’ Smaller cartridges typically fire bullets that are not heavy enough to penetrate deeply to reach the vital organs.
Examples of this function are represented graphically below.