Wednesday, March 30, 2011

The myth of handgun "stopping power": Part 1 of 3

(This is the first of three articles that will address this subject. Part Two may be found here, and Part Three here.)

I've been reading several articles, forum threads and other sources that are re-hashing the tired old subject of a handgun's 'stopping power'; the ability of a handgun bullet to stop an attacker with one or two shots. There's so much nonsense out there that I thought I'd tackle the subject myself, since I've needed it on more than a few occasions!

The first thing that worries me is that all too many people, including some who should know better, actually believe that 'stopping power' exists. Let's be blunt.

If you can't quantify something, you can't measure it.

'Stopping power' can't be quantified. It can't be assessed in feet and inches, or gallons and pints, or pounds and ounces. You can't say that weapon X, or cartridge Y, or bullet Z, have this or that many units of it. That means it cannot be measured; and, if it can't be measured, it doesn't exist as an objective reality. It's purely a subjective concept.

What we can quantify, and measure objectively, and assess experimentally, are a number of factors which can be used to assess the relative effectiveness in combat of different handgun cartridges, calibers, bullet types, etc. However, even these factors can't be combined into a single measurement that equates to 'stopping power', because there are many variables affecting each defensive situation and every shot fired.

The first factor to consider is the kinetic energy of the bullet. Energy is "the capacity to do work", according to the classic scientific definition. The bullet's energy must cause sufficient injury to an attacker, and/or cause sufficient pain, to stop his/her attack on us. Clearly, the more energy a bullet has, the more "capacity to do work" it possesses. A low-energy round may do more to annoy the target than to stop him! For example, earlier this month, two men chased down and captured their attacker after he'd shot them multiple times with a low-power handgun. Initially, they didn't even realize they'd been shot!

Two Live Oak men chased down their alleged assailant after being shot Friday, said LOPD Chief Buddy Williams.

The men, shot a total of five times with a .22-caliber handgun, apprehended the alleged gunman, 30-year-old Omar Garcia of 13567 116th Place, Live Oak, just as police arrived, said Williams.

. . .

Police say the men did not know they had been hit ...

. . .

Both victims, who remain hospitalized in Gainesville, are expected to survive, said Williams.

There's more at the link. Bold print is my emphasis.

(This isn't to say that a low-power cartridge such as a .22 Long Rifle can't kill someone. Clearly, if it hits a vital organ or blood vessel, it most certainly can! However, the report above illustrates that a low-power cartridge doesn't impart much of a shock to the human body. It can't be relied upon to stop [i.e. incapacitate] an attacker. No bullet, no matter how powerful, will do so if it only inflicts a flesh wound - i.e. one that affects a non-critical area of the body, missing all vital organs and/or blood vessels and/or major bone structures. Such injuries are unlikely to cause either death or incapacitation. We'll have more to say about that in Part 2 and Part 3 of this series.)

So, our first 'rule of thumb' is that the more energy a bullet has, the greater its potential to effectively stop an attacker. Here's a table of a number of common handgun, shotgun and rifle rounds, showing the energy each produces at the muzzle. (Being in the USA, I'm measuring velocity in feet per second and energy in foot-pounds. For the benefit of readers in countries using the metric system, I've provided conversions to, respectively, meters per second and joules.) All figures have been drawn from the Web sites of various ammunition manufacturers (e.g. Remington, Winchester, etc.), and are representative of similar loads from other manufacturers in the same cartridges/calibers and bullet weights.

(Click the table for a larger view)

You'll notice at once that even the most powerful handgun round listed (the .44 Magnum) has less than half the muzzle energy of the least powerful shotgun round (20 gauge #3 buckshot) and only a little over half the energy of the least powerful rifle round (.223 Remington/5.56x45mm. NATO). Briefly, the energy of almost any handgun round pales in comparison to the energy of almost any rifle or shotgun round. The only reason we'd use a handgun in a fight, in preference to a much more powerful long gun, is that the latter are much more difficult to carry around with us. A handgun can be readily and discreetly carried on our persons. Thus, its availability compensates (to some extent) for its deficiency in projectile energy. "A gun in the hand is worth two in the safe", as the saying goes.

Handgun cartridge size comparison. From left to right: an AA battery for reference purposes;
.44 Magnum; .357 Magnum; .38 Special; .45 ACP; .38 Super; 9mm. Parabellum; .32 ACP; .22 LR.

These energy figures are useful in comparing defensive cartridges to those that have a good track record of stopping aggressors in real life. I'm not going to go into the perennial controversy about 'one-shot stops'. It's both pointless and useless. The odds of stopping any fight with a single shot from a handgun are very slim indeed. It's normal for multiple shots to be needed, so I don't understand why so many shooters argue whether this or that round is more likely to stop the fight with a single shot. One of the top firearms instructors in the United States, Jim Higginbotham, has this to say on the subject:

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.

. . .

Circumstances in a real gunfight are unpredictable ... 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;
  • 5-8 with a 9mm.

There's more at the link.

I wholeheartedly endorse Mr. Higginbotham's conclusions from my own experience of handgun combat (which spanned 18 years of severe civil unrest in another country). I'll add this to them: the more energy a round is able to transfer to an assailant, the more effective it's likely to be at neutralizing him. Note that mere possession of energy does not guarantee that a round will be more or less effective than another: it has to actually transfer that energy on demand. Remember, energy is "the capacity to do work". Unless that energy is dumped into the attacker, it can't work on him.

The 'average' standard-pressure .45 ACP or .45 Colt round will offer between 350-425 foot-pounds of energy at the muzzle; a .40 S&W will offer 375-450; and a standard-pressure 9mm. will offer 325-400. If we average out these figures, we get a range of 350-425 foot-pounds of energy (or 474-576 joules, for those who think in metric terms). If our selected cartridge falls within this range, and is able to transfer that energy to the target, it's likely to be a reasonably effective defensive round, given a few good, accurate hits on the assailant. Less than that, and it may not be as effective as we'd wish. More than that, and it may be even more effective: but there's a flip side to the energy 'coin'.

Remember Newton's third law of motion?

"To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions."

The energy imparted to a bullet by the burning propellant in a cartridge case is matched by the energy imparted by that same propellant to the gun from which it's fired. If the bullet's leaving the barrel with an energy of, say, 400 foot-pounds, the gun is going to recoil in your hand(s) with the same 400 foot-pounds of energy. Now, because the gun's a lot heavier than the bullet, its weight absorbs much more of the recoil energy, reducing the amount that reaches your hands; and it spreads that energy out over the area of the grip, meaning that much less of it affects any particular point on your hand. Still, you have to control the gun against the 'kick' of that recoil energy, and bring it back into line for a follow-up shot if necessary (and, as we've seen, that's more likely than not to be required!).

Clearly, the heavier the handgun, the more recoil energy it will absorb; but, the lighter the handgun, the more recoil energy it will make you absorb. Similarly, the more surface area there is on the grip for your hand to grasp, the more the recoil impulse will be spread across your hand; while on a smaller grip, the recoil impulse will be more concentrated, and you'll feel it more. This is illustrated by the picture below, which depicts all five semi-automatic models of Glock pistols chambered in the 9mm. Parabellum caliber. Clockwise from top left, they are the Model 17L, Model 19, Model 26, Model 17, and Model 34.

(Image courtesy of Ken Lunde)

It will be readily apparent that the full-size frame of the Models 17, 17L and 34 will spread the recoil across more of your hand than the compact frame of the Model 19, and far more than the diminutive frame of the sub-compact Model 26, which is so small that it offers only a two-fingered grip. As a result, even though they fire identical cartridges, the felt recoil of the Model 26 will be considerably greater than the full-size models.

Weight and size considerations should directly affect your choice of a handgun and the caliber or cartridge for which it's chambered. It's counter-productive (even dangerous) to select a handgun with more recoil than you can effectively control. If you're not going to shoot it often, a lighter-recoiling gun is almost mandatory, because it takes regular practice to control a hard-kicking weapon. Even if you're going to practice regularly, your physical size and build, muscular strength and dexterity, and any injuries or infirmities, will directly affect 'how much gun' you can control. I've trained many disabled and/or handicapped shooters who were unable to handle anything more than the minuscule recoil of a .22 Long Rifle cartridge. Nevertheless, despite its shortcomings, by learning to shoot it fast and accurately, they became better able to defend themselves against attack.

Therefore, before investing your hard-earned money in a handgun, learn how it fits your hand, how it recoils when shooting good defensive ammunition (which is usually more powerful than cheaper 'range' or 'practice' ammo), and whether or not you can control it in rapid, accurate fire on a target. Ask your friends with guns to let you shoot their weapons; patronize a shooting range that rents out various kinds and calibers of handguns; and attend a suitable introductory training course where you can ask questions.

That's enough for the first article in this series. In Part 2, we'll examine how bullets cause injury, and how to select ammunition that's suitable for defensive use. In Part 3, we'll look at bullet placement, and why that's the most critical aspect of all when it comes to using a handgun for self-defense. Only when all these factors are considered together will we be able to draw any conclusions about handgun 'stopping power' (or, rather, the myth thereof).



Joe in PNG said...

Sadly, in times past I have fallen for the "more stopping power" meme. This has resulted in buying pistols that were agony to shoot(the Kel-tec PF-9 being the most painful example).
And because those guns were painful to shoot, I did not want to shoot them. Not exactly the best plan for a defensive firearm!

So, even if 9mm/.38spec are "wimp calibers", at least I can hit something with them.

Anonymous said...

The best way to stop a person in their tracks is to shot low and break their pelvis.

No amount of pain killer or muscle matter because with a broken pelvis they all fall down. This however does not stop them from shooting.

hydrogeek said...

That chart is a thing of beauty. It's also why, even though I love and carry handguns, my "house gun", kept near my bed for home protection is a 12 gauge shotgun. Thanks for this article, I may be forwarding it on to some people!

Peter said...

Anonymous at 9.26 a.m. - Sorry, but that's not so. The pelvic bone itself is hard to hit (particularly in a moving target); and you have to not just put a hole in it, but break it - shatter it - to put someone down. Most handgun rounds are too small and weak to do that. The "pelvic stopping shot" is largely a myth, except with high-powered rifles and shotguns.

You're much better off (with a handgun) to aim for center-of-mass and try to take out brain or spinal cord, or some of the major organs and blood vessels in the torso.

Anonymous said...

As a practicing forensic pathologist, I am unimpressed with "stopping power" and the "one shot stop". If I want stopping power, I'll take a 12 gauge.

I also think comparing data from police shootings and non-police self-defense shootings are comparing apples and oranges. The police need to affect an arrest or a stop. The non-LEO does not, and has the ability to run away from a fight that the police do not have.

That said, pick the gun you like and can shoot accurately, and worry about shot placement. I've seen police shootings where only 10 bullets out of 40 actually HIT the target. The other 30 were wasted.

STxRynn said...

Excellent and to the point. If you don't dump all the energey the bullet continues to fly through the target to parts unknown. During the Kent State shooting, on M1 round passed through two, and if I remember correctly continued on for about a mile. Not much energy dump there.

Particularly vived is shoot until it changes shape or catches fire. I can deal with that!

Thanks for your continued service to your "extended family"!!

Geodkyt said...


I agree with you in some regards, and disagree with you in another.

First off, the "stopping power" of any "service pistol" load with modern hollowpoints is so similar to every other "service pistol" with modern hollowpoints as to make caliber your primary choice laughable.

Second, I seem to recall the statistic that goes, "Roughly half of anyone, shot anywhere, with anything 'stop' nearly immediately." That includes .25ACP ball grazing the arm and a .44 Magnum between the running lights. Which means that half of people shot don't stop immediately as a "one shot stop". Which brings me to my thrid point. . .

While denying the existance of a true "one shot stop" cartridge, I will am willing to use relative stopping power comparisons to help me select which cartridge I will prefer, which I will then shoot "until the target changes shape or catches fire", on the theory that even if it isn't a "one shot stop" by Marshall-Sanow rules, a "six shot stop" beats the Hell out of a "seven shot stop". . . especially if you happen to be carrying a six shot revolver. {grin}

But in the end, see Point #1 -- if size/weight/familiarity/whatever cause you to prefer a different cartridge than the supposed "best", cool. . . chances are, it'll work just about as well. The .380 in your hand beats teh 12 gauge in the safe, and you can't miss enough with a .357 Magnum to beat hits from a .38 Special.

Anonymous said...

Yeah someone got shot 5 times with a .22lr and never noticed it. Ok, lol! I smell disinfo or the guy really had no aim to speak of. If you get shot once in the arm, once in the leg, once on the pelvis and once in the chest then OBVIOUSLY even .45acp won't help you.

Anonymous said...

I know this an ancient(in web time)post, but after rereading it for probably the twentieth time, I
noticed an insignifigant error.

In the paragraph talking about the picture of Glock pistols, you state the model numbers as
beginning clockwise from the top left. I'm pretty sure that should be clockwise from the top right.

Kinda anal, I know, but if I found something like that in my own writing, it would bug the heck out
of me.

Thanks for leaving all these old posts accesible from your home page. It's a great reference source.

Keith P