Ballistic studies and lethal potential of tear gas pen guns firing fixed metallic ammunition.

Illegal older model and foreign-made tear gas pen guns as well as illicitly manufactured pen guns were used to fire revolver or pistol cartridges of calibers .22, .25, .32, .38, .44 Special, and .44 magnum, as well as rifle cartridges of caliber .270. Velocity, range of accuracy, impact kinetic energy, and gelatin block penetrability of bullets fired from the various cartridges are presented. The characteristics of recovered bullets, cartridge casings, and firing pin impressions are described, and the hazards of these weapons to users and potential victims are discussed.