Self defense, stopping power, and caliber, Part 4

Tuesday, April 08, 2008 Filed in: Ammunition, General gun stuff, Techniques & Training

(For convenience, you can access all the installments of this series at this link.)

The bullet is more important than the caliber.

We know that our bullet needs to do damage to whatever important thing it manages to find. How, exactly, is that going to occur? It just so happens that most animal tissue (including that of the violent felon who has just attacked you) is remarkably elastic, and consequently difficult to damage. Most tissues have a tendency to "close up" around puncture wounds, in the same way that they close up after a hypodermic needle withdraws. If they didn't, every time we get a booster shot we'd spring a leak!

The upshot (pardon the pun) of this is that our bullet needs to die-cut or crush the tissues in its path, rather than sliding cleanly through. The reputation of the old .38 Special 158 grain round nose bullet as a "widow maker" was well deserved, as it often went in one side and out the other with very little blood loss. That smooth, aerodynamic profile travels through water-filled tissue about as cleanly as through air, for all the same reasons. It neatly parts that tissue in a way that facilitates immediate closure and minimal blood loss. In our sefl-defense scenario, that's what's known as "A Bad Thing."

In fact, round nose (or "ball") ammunition is an unremarkable performer in just about any caliber; "they all fall to hardball" is right up there with "the check is in the mail" for statements you should never believe, no matter how authoritatively (read: arrogantly) delivered.

If we can get a bullet to cut or crush a non-closing hole in the target, we stand a better chance of doing the kind of work necessary to cause that target to stop in its tracks.

The amount of disruption that a handgun bullet delivers to the target is dependent on its shape/construction and on the overall diameter (caliber.) A shape that encourages efficient travel through the target is to be avoided; a shape that is non-aerodynamic will generally produce the kind of result that we seek. All other things being equal, flat-faced bullets usually beat pointy bullets.

(Personally, I pay more attention to bullet construction than caliber. Hunting and shooting experience, plus a lot of research with those more knowledgeable in the field of wound ballistics, has convinced me that there is more variation in effectiveness within calibers than between them. In other words, you're more likely to see performance differences by changing your bullet type, rather than changing calibers. )

This isn't news to any old-timers out there! Hunters in bygone days were always told to use flat-pointed bullets over round-nosed varieties, because they delivered more "shock" to the quarry. That was their non-scientific way of explaining why the bullets obviously performed differently, and what they lacked in technical jargon was more than compensated by their acute observations.

Of course there just isn't a free lunch; those flat bullets don't usually work in autoloading actions, and they make speed reloading of a revolver more difficult. There is an answer: the expanding bullet. We can actually enhance the terminal results by using a bullet (usually a hollowpoint of some sort) that grows in diameter as it goes through the target.

A hollowpoint bullet works because, as it enters the target, it expands to a greater-than-caliber frontal diameter and assumes a very flat-faced shape. This means that the bullet can crush a much larger hole than normally possible for the caliber, ensuring the kind of target damage necessary to complete the task at hand.

There are, of course, issues in making these things perform as desired: first, the work of deforming the bullet takes energy. This energy can only be come from the bullet itself, which means there is that much less available to enable the bullet to continue its travel. Second, the resulting increase in drag from that wide face also uses energy at a tremendous rate, and thus also drastically limits penetration. Because of these factors, shallow wounds from hollowpoint bullets are not at all unheard of, both in hunting and in self defense.

The solution is to a) use a different cartridge that has enough energy to spare to begin with, or b) increase the energy of the existing cartridge. We'll tackle those issues next time!

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-=[ Grant ]=-

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