Physical forms of contemporary small-arms propellants and their forensic value

Intermediate gunshot wounds typically produce powder tattooing and/or stippling of the skin. The size and density of such powder-induced injuries around an entry wound are used to estimate the separation distance between the muzzle of the responsible firearm and the entry site through test firings at selected muzzle-to-target distances, with ammunition comparable to the injury-producing round and the evidence firearm. The foregoing is well known to forensic pathologists who document and describe such powder patterns in gunshot victims and firearm examiners who customarily produce the test-fired powder patterns for subsequent range-of-fire determinations. Less known, particularly to pathologists, is the considerable variety in forms of modern nitrocellulose propellants, their effects on powder-induced injuries to human skin, and the value of these varied physical forms in the reconstruction of shooting incidents. These factors are the subject of this article.