Firearms Tactical Institute
Work of the U.S. Government; not subject to copyright in the United States.
Web Site Index and Navigation Center
U.S. Department of Justice
Handgun Wounding Factors and Effectiveness
Special Agent UREY W. PATRICK
FIREARMS TRAINING UNIT
July 14, 1989
From page 5:
Mechanics of Handgun Wounding
All handgun wounds will combine the components of penetration, permanent cavity, and temporary cavity to a greater or lesser degree. Fragmentation, on the other hand, does not reliably occur in handgun wounds due to the relatively low velocities of handgun bullets. Fragmentation occurs reliably in high velocity projectile wounds (impact velocity in excess of 2000 feet per second) inflicted by soft or hollow point bullets.10 In such a case, the permanent cavity is stretched so far, and so fast, that tearing and rupturing can occur in tissues surrounding the wound channel which were weakened by fragmentation damage.11,12 It can significantly increase damage13 in rifle bullet wounds.
Since the highest handgun velocities generally do not exceed 1400-1500 feet per second (fps) at the muzzle, reliable fragmentation could only be achieved by constructing a bullet so frangible as to eliminate any reasonable penetration. Unfortunately, such a bullet will break up too fast to penetrate to vital organs. The best example is the Glaser Safety Slug, a projectile designed to break up on impact and generate a large but shallow temporary cavity. Fackler, when asked to estimate the survival time of someone shot in the front mid-abdomen with a Glaser slug, responded, "About three days, and the cause of death would be peritonitis."14 (My emphasis - SS.) In cases where some fragmentation has occurred in handgun wounds, the bullet fragments are generally found within one centimeter of the permanent cavity. "The velocity of pistol bullets, even of the new high-velocity loadings, is insufficient to cause the shedding of lead fragments seen with rifle bullets."15 It is obvious that any additional wounding effect caused by such fragmentation in a handgun wound is inconsequential.
Of the remaining factors, temporary cavity is frequently, and grossly, overrated as a wounding factor when analyzing wounds.16 Nevertheless, historically it has been used in some cases as the primary means of assessing the wounding effectiveness of bullets.
Dr. Fackler, a former U.S. Military trauma surgeon, is one of the foremost wound experts in the world. Duncan MacPherson is a real rocket scientist who worked with Dr. Fackler on the math / physics behind the wounding mechanisms that Dr. Fackler observed in his medical practice. MacPherson wrote THE seminal text on the subject, Bullet Penetration Modeling the Dynamics and Incapacitation Resulting from Wound Trauma. I finally got a copy. It's a mathematically rigerous study, and tough reading for someone who graduated from engineering school in 1965. Basically it discounts most of what we read from the gun magazines, and debunks "kinetic energy dump", "hydrostatic shock", Taylor K.O. formula, Sanow's works. All the relatively easy-to- understand intuitive stuff.