Stopping Power

Last night’s Gun Nuts Radio, after the ancillary discussions on news items and other sundries was supposed to focus on stopping power and specifically handgun wounding mechanics.  If you’d like to download and listen to last night’s Gun Nuts Radio, just click here.  Of course, you can also always get an .mp3 copy of the show, or for iPod/iPhone users, subscribe to the show on Gun Nuts Host - Gun Nuts Radio: The Next Generation of Shooting | Blog Talk Radio Feed - Gun Nuts Radio: The Next Generation of Shooting | Blog Talk Radio Feed.

Unfortunately, we didn’t really have the time to get into the meat and potatoes of stopping power and handgun wounding ballistics, and that’s partly my fault – it’s is a fairly technical and dry (read: boring) topic that unfortunately doesn’t translate well to radio. The source document for much of what I’m about to talk about can be found here, it’s the FBI’s document that explains the rational behind their standards for defensive pistol ammo. It’s only 19 pages, and while it’s kind of technical in some places, it’s also a very good read for anyone who wants to really understand terminal wounding ballistics. Projectiles wound in one of four ways, or which only a couple apply to handguns:

  1. Penetration – the tissue destroyed by the passage of the projectile
  2. Permanent cavity – the volume of tissue destroyed by the passage of the projectile
  3. Temporary cavity – Expansion of permanent cavity by stretching due to kinetic energy.  While this type of wounding is seen with handguns, it’s effectiveness at stopping a fight is often grossly overstated.
  4. Fragmentation – secondary projectiles, bone fragments, etc which create their own wound channels.  Not often seen with handguns unless specialized ammo is used.

The reason why the “temporary cavity” honestly doesn’t matter with pistol bullets is due to the elasticity of most human tissue – the temporary cavity caused by pistol rounds doesn’t significantly stretch the tissue enough to do damage.  As such, the permanent cavity is the only wounding mechanism in pistol bullets that can be reliably measured as an indicator of “stopping power”.

Of course, the problem that most people fail to realize in this is stated in the FBI document: “…the concept of reliable and reproducible immediate incapacitation of the human target by gunshot wounds to the torso is a myth.”  Even if you were to destroy the heart of a hypothetical attacker with your first shot, the brain contains enough oxygen to support 10-15 seconds of voluntary activity after that; this also does not take into account attackers that may be chemically enhanced by various drugs.  Ultimately, a gunfight is tremendously dynamic experience, because those of us that carry guns for self defense cannot in any way control for the various mental factors that contribute to a projectile’s effectiveness.  This is what lead to the FBI’s rational that a bullet must be able to penetrate 12 inches of soft tissue regardless of expansion to be an acceptable projectile for law enforcement use – which became the basis for the FBI Protocols for bullet testing.

Again, I encourage everyone to check out last night’s Gun Nuts Radio for more information on stopping power and terminal ballistics.  For further reading, please refer to the FBI’s source document on handgun wounding.