In the wake of the spate of recent terrorist and criminal incidents, I've again been getting queries about what cartridge or caliber is 'best' for self-defense. In particular, some folks with what they consider to be 'old-fashioned' heavier-caliber weapons are asking whether they need to go to lighter caliber equivalents that can hold more ammunition. Whilst there are definitely factors that favor such a switch, there are others that motivate against it.
I've written extensively about this in the past, and I don't want to re-hash everything here; but for the benefit of those who may have missed earlier articles, I'll provide a brief summary. See these previous articles for more in-depth information:
- Bullet and cartridge effectiveness for self-defense
- The changing urban self-defense environment
- The myth of handgun "stopping power": Part 1, Part 2 and Part 3
Nevertheless, larger rounds retain a significant advantage in terms of bullet momentum and its resultant effects on the target. I discussed momentum in the third part of my 'Myth of handgun stopping power' series; please read the discussion there. Briefly, momentum (and hence depth of penetration) is generally improved with a heavier bullet, while velocity (and hence bullet energy) is generally improved with a lighter bullet. (That's an over-simplification, but in a brief overview like this, it'll have to do.)
Whilst maximum energy delivery on target is an important aspect of a defensive round, momentum has a value all its own when it comes to penetration. Examples include the need to penetrate concealment such as vehicle bodies, or deal with heavy-set attackers (i.e. having greater volumes of flesh and hence distance to penetrate between their skin and their vital target zones), or get through heavy outer clothing such as multiple layers worn in colder climates. A round with greater momentum will generally penetrate more easily, and penetrate deeper into, such targets.
There's also the issue of the shock delivered to the target. I think it's unquestionable that a heavier bullet, with greater frontal area and momentum, will deliver a greater initial shock to the target. I offer two real-world tests that you can conduct for yourself.
The sport of bowling pin shooting has become very popular over the years. Briefly, the shooter engages a table full of bowling pins and attempts to not just knock them down, but drive them off the table, as fast as possible. Here's a video clip demonstrating the sport.
There are classes of competition for smaller, less powerful cartridges, even down to the lowly .22 Long Rifle (using smaller, lighter targets, of course); but in general, for the same size and weight of bowling pin, a larger, heavier, more powerful cartridge will be more effective than a smaller, lighter, less powerful one. Try this for yourself. Set up a big, heavy bowling pin on a table-like surface six feet in depth behind the bowling pin. Shoot at it with both a heavier and a lighter caliber, using the same point of aim. (I suggest .45 ACP and 9mm. Parabellum, two of the most-used defensive cartridges.) See which one knocks it down more easily, and drives it further back down the surface. See which one knocks it right off the rear of the surface more quickly. I think you'll find that the heavier cartridge does better than the lighter one, almost all the time.
The second real-world test is hunting. Many hunters have shot game animals roughly the same weight as (or sometimes heavier than) human beings with handgun cartridges. All too often, rounds that are very highly rated for self-defense against humans don't do well at all against such animals. One of my favorites, Winchester's RA9TA 127gr. 9mm +P+ round, did very poorly for my friend Lawdog in an encounter with a wild hog. (On the other hand, so did a .45 ACP round from the next officer to arrive on the scene.) Jim Higginbotham, a firearms instructor and active shooter with decades of experience whose views I respect very highly, reports that the fabled 125gr. .357 Magnum round, beloved of experts for many years, has performed very poorly on deer in his hands, as have many 9mm. rounds. On the other hand, he's used .45 ACP on deer with good results. (Admittedly, whitetail deer are generally a lot less tough than wild hogs!) My own favorite cartridge for handgun hunting (not that I do a lot of that these days, since my disabling injury) has long been the Federal 300gr. CastCore load in .44 Magnum. In general, larger calibers and cartridges have performed better on human-size and -weight animals than smaller ones.
This is not, repeat, NOT, to say that a 9mm. pistol or .38 Special revolver can't be a perfectly satisfactory means of self-defense against a human being! They most certainly can, particularly when loaded with an effective round that's accurately directed against a suitable target zone. I carry such cartridges almost every day, and I'm comfortable relying on them. However, I also accept that they have their shortcomings, some of which we've discussed above. I saw those shortcomings magnified in actual combat in southern Africa during the 1980's (admittedly with earlier-generation ammunition that wasn't as advanced as modern versions), and I therefore remain more comfortable with larger, heavier, more powerful cartridges than I am with smaller, lighter, lower-powered alternatives. When I'm carrying the latter, I expect to have to use more rounds to achieve the same results that I would with fewer rounds of the former.
Jim Higginbotham's comments bear repeating. I endorse them from my own experience (which, I hasten to add, is far less than his!).
Your skill is far more important that what you carry, within reason. We are not really talking about “stopping power”, whatever that is, here but rather effectiveness.
I can find no real measure – referred to by some as a mathematical model – of stopping power or effectiveness. And I have looked for 44 years now! Generally speaking I do see that bigger holes (in the right place) are more effective than smaller holes but the easy answer to that is just to shoot your smaller gun more – “a big shot is just a little shot that kept shooting”. True, I carry a .45 but that is because I am lazy and want to shoot less. A good bullet in 9mm in the right place (the spine!) will get the job done. If you hit the heart, 3 or 4 expanded 9mms will do about what a .45 expanding bullet will do or one might equal .45 ball . . . IF (note the big if) it penetrates. That is not based on any formula, it is based on what I have found to happen – sometimes real life does not make sense.
. . .
In real life, your gunfight may be dark, cold, rainy, etc. The subject may be anorexic (a lot of bad guys are not very healthy) or he may be obese (effective penetration and stopping power of your weapon). There are dozens of modifiers which change the circumstance, most not under your control. My only advice on this is what I learned from an old tanker: “Shoot until the target changes shape or catches fire!” Vertical to horizontal is a shape change, and putting that one more round into his chest at point blank range may catch his clothes on fire, even without using black powder.
We tell our military folks to be prepared to hit an enemy fighter from 3-7 times with 5.56 ball, traveling at over 3,000 feet per second. This approach sometimes worked, but I know of several cases where it has not, even “center mass.”
With handguns, and with expanding bullets, it is even more unpredictable, but through years of study I have developed a general formula, subject to the above mentioned unpredictable circumstances.
- 2-3 hits with a .45
- 4-6 with a .40
With a revolver, the rounds are not necessarily more effective but I would practice shooting 3 in a .38 or .357 merely because I want 3 left for other threats. Not that those next three won’t follow quickly if the target hasn’t changed shape around my front sight blade. A .41, .44 or .45 Colt I would probably drop to two. Once again, they are not that much more effective than a .45 Auto but I don’t have the bullets to waste.
- 5-8 with a 9mm
In any case, I want to stress the part that it is more about how you shoot than what you shoot, within reason. It is also more about the mindset and condition of the subject you are shooting which is not under your control. Take control – buy good bullets and put them where they count the most! And remember “anyone worth shooting once is worth shooting a whole lot!”
There's more at the link. Sage advice, and worth following, IMHO.
I hope this discussion has helped to clarify the situation. Don't rely on my words alone! There's an immense volume of material out there. Read widely, and learn from as many sources as you can.