Friday, April 1, 2011

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

Part 1 of this series focused on analyzing 'stopping power' (and demonstrating that it doesn't exist as an objective, measurable reality), and went on to look at bullet energy. Part 2 examined the way in which bullets inflict injury, and problems that may arise in that connection. This final part will examine what sort of injuries disable an attacker, target areas of the body, and points of aim. It will conclude by considering a few general questions about the use of a handgun in self-defense.

Basically, there are only three ways, or 'mechanisms', guaranteed to stop an attacker from continuing his assault. One is to break down the framework of his body - i.e. the skeleton - in such a way that it no longer functions as a foundation for movement. This is hard to achieve in practice. For a start, to break bones requires a precisely-placed blow. If one's target is moving (e.g. running at you, or towards your spouse or children), hitting a leg bone, or the pelvis or spine, is not easy. Also, a major bone is strong and tough - it has to be! It can absorb quite a lot of punishment. If you're using a relatively low-powered handgun, or round-nosed bullets that might bounce off bone rather than dig in, you may not succeed in breaking a vital bone. Therefore, this is the least trustworthy mechanism for self-defense.

The second mechanism is to interrupt the body's motor control. This requires shutting down one or more of the following three components of the central nervous system.

  • The cerebellum is "a region of the brain that plays an important role in motor control ... The cerebellum does not initiate movement, but it contributes to coordination, precision, and accurate timing. It receives input from sensory systems and from other parts of the brain and spinal cord, and integrates these inputs to fine tune motor activity."
  • The brain stem contains "the nerve connections of the motor and sensory systems from the main part of the brain to the rest of the body ... This includes the corticospinal tract (motor), the posterior column-medial lemniscus pathway (fine touch, vibration sensation and proprioception) and the spinothalamic tract (pain, temperature, itch and crude touch). The brain stem also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system, and is pivotal in maintaining consciousness and regulating the sleep cycle."
  • The spinal cord "functions primarily in the transmission of neural signals between the brain and the rest of the body but also contains neural circuits that can independently control numerous reflexes and central pattern generators. The spinal cord has three major functions: A. Serve as a conduit for motor information, which travels down the spinal cord. B. Serve as a conduit for sensory information, which travels up the spinal cord. C. Serve as a center for coordinating certain reflexes."

This is the most trustworthy mechanism for self-defense. If you get a good, solid, bullet strike to any of these components of the central nervous system, your attacker will drop right there. He may not be killed, but he'll certainly be disabled, probably for the rest of his life. However, all three components are well protected by bone. Hitting them requires accuracy, and a bullet that has enough energy and momentum to penetrate through their defenses.

The third mechanism, and the one most vulnerable to damage by defensive fire, is to interrupt the body's circulatory system. This can be done by either shutting down the heart, or by damaging one or more major blood vessels, causing severe blood loss. Either injury will deprive the central nervous system - i.e. the brain - of its blood supply, which carries oxygen to it. Oxygen deprivation will shut it down in due course. However, interrupting the circulation may not produce an immediate effect on an attacker. Even if the heart is destroyed by gunfire, the brain will have enough oxygen in its tissues (and in the blood currently circulating through it) to function for several seconds, depending on the individual and his state of excitement or agitation (which will release adrenaline into his system). During that time, an attacker can continue to assault his victim, potentially inflicting serious or even fatal injuries.

I mentioned that these three mechanisms were 'guaranteed' to stop an attacker, if they worked. There's a fourth mechanism that will sometimes stop an attacker; but it isn't guaranteed to work. That mechanism is pain. If the injuries you cause to your attacker produce enough pain, he may stop his attack and either run away, or cease moving because it hurts too much to do so. However, an attacker who's high on drugs, or drunk, or simply on an 'adrenaline rush', may not feel pain as acutely as a normal person; so he may not react in any of these ways. Furthermore, some people are less sensitive to pain than others. Pain will almost certainly be produced as a side-effect or secondary effect of any wound we inflict on an attacker; but because it can't be guaranteed to stop an attack in and of itself, it's not the primary effect we seek to achieve.

Now that we've examined the mechanisms that will stop an attacker, let's look at the vulnerable areas of the human body, and where we need to aim our bullets in order to do so.

(All original images courtesy of Wikipedia, edited and annotated by the author.
1 - Cerebellum
2 - Brain Stem
3 - Heart
4 - Aorta, and the major blood vessels above the heart)

You can see most of the primary target zones numbered in the image above: the cerebellum (1), the brain stem (2), the heart (3), and the aorta (4). The latter also shows the position of the other major blood vessels above the heart. The very narrow blue rectangle running from the chin down to the navel illustrates the position of the spinal column, which encases and protects the spinal cord.

The largest target (and therefore the easiest to hit, particularly under the stress of a fight-or-flight response, and while moving and/or engaging a moving target) is the heart and its major blood vessels. These are surrounded by other major organs: the lungs, above and on either side; the liver; the pancreas; the spleen; and, lower down, the kidneys, which are on either side of and slightly below the stomach, sitting above the intestines.

To locate the best point of aim on the torso, imagine a line drawn horizontally across the chest from armpit to armpit; then imagine another line running vertically down the body, in line with the spine. The point of intersection of these lines (drawn in yellow on the image above, and in red on that below) is about halfway up the sternum. This is our primary point of aim. If our bullets strike in a six- to eight-inch circle centered on this point (shown in red above), they'll damage the heart, and also affect the blood vessels above it. If they penetrate deeply enough, they can also hit the spinal column, and may injure the spinal cord.

Some instructors teach that our point of aim should be the "center of mass", the vertical center of the torso from hips to neck. They advise that our point of aim should be at the intersection of the same vertical line, and a line drawn between the nipples (the latter shown in yellow on the image below). This is not anatomically correct. If we aim that low on the torso, shots that impact below our point of aim won't affect the heart, and are less likely to hit the aorta as it runs vertically down the torso, behind the other organs. Furthermore, injuries to organs such as the liver, pancreas and spleen (shown in the enlarged image below), while painful and potentially very serious, may not stop a determined or drugged or drunk attacker before he's had time to injure us very severely. A higher point of aim will cover more of the heart and the major blood vessels above it, giving our bullets a better chance to disrupt the circulatory system. So, if you're told that "center of mass" is the desired point of aim, remember that we need to aim a bit higher than the "center" for best results.

Human torso, showing internal organs (image courtesy of Wikipedia)

If we hit the cerebellum, brain stem or spinal cord with an effective bullet, it's a guaranteed fight-stopper. However, they're relatively small targets, and are protected by the skull and the vertebrae of the spinal column. The latter is also buried beneath the full depth of the torso, meaning that we'll need a deep-penetrating round to reach it from the front. Furthermore, our attacker is unlikely to be standing still; and we're likely to be moving ourselves, either backpedaling to avoid his attack, or trying to make ourselves a more difficult target for incoming fire. All those factors make it harder to hit these targets. Nevertheless, because they're the most certain way to stop an attacker, they remain of primary importance. If our attacker simply won't stop his assault, we can try to slow him down by hits to his limbs or torso, then take more careful aim at a central nervous system target to end the problem.

The spinal cord runs the length of the torso, and up through the neck into the base of the skull (as outlined in blue in the first image above). Any shot fired centrally into the front of the torso has a chance to reach it, provided the bullet possesses sufficient energy and momentum to punch through the full depth of the torso and the 'armor' of the spinal column. The cerebellum and brain stem are located at the base of the brain, deep within the skull, as shown by the numbers 1 and 2 on the first diagram above. Our shots should be aimed at the inverted triangle (outlined in red on the face of the first figure above) formed by the top outer corners of the orbits of the eyes, and the base of the nose, to reach these targets. The orbits and the nasal cavity offer little resistance to penetration by bullets, unlike the thicker bone elsewhere in the skull.

Of course, the images above are an idealized representation of our target zones. In real life, our attacker is most unlikely to be standing still, or directly facing us, waiting for us to shoot! He'll be moving as fast as he can, and may be turned at an angle from us. Furthermore, his torso may be obscured by his hands or arms, or by something he's carrying. He may even be hiding behind one of our loved ones, trying to prevent us shooting at him. We have to select a target we're sure we can hit, and shoot at it until such time as our bullets take effect.

Imagine the heart placed centrally in the torso, from front to back and side to side. Have a friend turn around slowly in front of you, and try to visualize the placement of the heart within his or her chest as they do so. The horizontal line between their armpits remains your guide as to the height of the heart; so imagine that line constantly running across the width of the torso, no matter what its angle to you. Take a line down the middle of the torso, from neck to hips, as it is presented to you at any moment. The intersection of those lines is your point of aim, irrespective of the direction in which your target is facing at the time. For a head shot to the cerebellum or brain stem, examine the first image above. Note that both targets are positioned roughly level with the ears, and in the rear half of the skull. Your point of aim is thus a band between the top and bottom of the ear, irrespective of the angle of the head; and towards the back half of the skull (although this will obviously depend on the angle at which the head is turned). However, bear in mind that the outer shell of the skull is fairly thick, heavy bone. A low-powered bullet may not be able to penetrate it, or may bounce off if it comes in at an angle.

If your aim is obstructed by something (a hostage, or an object the attacker is carrying, or something behind which he's sheltering), then try to hit what you can see. If you shoot his foot or ankle, the target may drop to one knee. Shoot the knee, and the target may fall down, exposing a hip. Shoot the hip, and the target may roll away, presenting something else to shoot at. To repeat Clint Smith's words (which I mentioned last night): "Shoot what's available, as long as it's available, until something else becomes available." (However, bear in mind that you're only entitled to use deadly force to stop the threat. As soon as the threat is over - i.e. the attacker has surrendered, or is too badly injured to continue the assault - we no longer have the legal right to use lethal force in our defense. That's a critically important point; and if you disregard it, you will almost certainly find yourself facing both criminal charges and a civil lawsuit from the attacker - now the victim - and/or his surviving family.)

Another thing: remember the difference between cover and concealment. Cover is something that both hides someone from view, and protects them against incoming fire (e.g. a concrete wall). Concealment hides someone from view, but does not protect them against incoming fire (e.g. a curtain, a drywall panel, a sofa, etc.) Too many people think that they can't shoot at someone who's sheltering behind something. That's only true if the shelter is cover. If it's concealment, your bullets will still penetrate it. (The corollary is, make sure you and your loved ones are behind cover whenever possible, not just concealment!)

All right. We've covered what to shoot with, and what to shoot at. I'm not going to cover how to shoot, because that's a whole field in itself. However, there are a few final points to discuss in relation to the mythical field of 'stopping power'.

We discussed bullet energy in the first article in this series: but we didn't mention bullet momentum. Momentum can be defined as an object's "driving power or strength". It's different from energy: but, just as energy is conserved, so is momentum. Furthermore, while the energy of an object is determined by multiplying its mass by the square of its velocity, its momentum is calculated as mass multiplied by simple velocity - in other words, the mass of the object contributes much more to its momentum than it does to its energy. This explains why heavier bullets have more momentum than lighter ones, and usually penetrate deeper in flesh, even if they have the same raw energy as the lighter bullet.

Let's take two examples from the table of bullet energy provided in Part 1 of this series. The 115-grain 9mm. Parabellum round, and the 200-grain .44 Special round, have almost identical energy (within 5 ft/lbs. of one another, less than a 2% difference); but the former bullet is 33% faster than the latter, while the latter bullet is 74% heavier than the former. What does this mean for their respective momentum?

(A tip o' the hat to the good people at, whose very useful energy and momentum calculator produced these bullet momentum figures.)

As you can see, the heavier bullet has significantly more momentum than the lighter bullet, despite their almost identical energy levels. Therefore, the heavier bullet will be harder, and take longer, to slow down. It can be expected to penetrate deeper into flesh than the lighter bullet. That's an important asset if you have to punch through a thick-set torso to reach the spine, or shoot through the attacker's raised arm in order to penetrate his chest and puncture his heart. This principle applies across all calibers and energy levels. The heavier the bullet, the greater its momentum.

I recommend the following steps when selecting a round for self-defense.

  1. Determine the most powerful cartridge you can handle in aimed, rapid fire (i.e. controlling its recoil, aiming the gun again, firing another shot, and repeating the process for a full magazine, or - in actual combat - until the threat[s] is/are nullified). It's no good selecting a cartridge on the basis of its power, or energy, or momentum, if you can't shoot it accurately and rapidly. As more than one authority has pointed out, "You can't miss fast enough to win" - whether in a shooting competition or in a gunfight!
  2. Purchase a reliable, trustworthy handgun in that caliber. Ensure that it's a gun you can control! There's no point in firing a very powerful cartridge out of a very light or very small gun - it'll be extremely unpleasant, and possibly too painful for regular practice. The size and weight of the gun are as important as the power of the round in determining what you can control . . . but they also limit what you can carry. It's no good selecting a gun that's heavy enough to make a powerful cartridge manageable in your hands, but is so heavy it's uncomfortable to carry in a holster all day.
  3. Determine the energy levels of the defensive cartridges available in that caliber. Try to list all those available, in descending order of their muzzle energy. (Note that I emphasize defensive cartridges. Many calibers offer loads designed for hunting or target use, which are not optimum for combat. Such ammo is better than nothing in a pinch, but there are usually better choices for defense.)
  4. From among the top few defensive rounds in terms of muzzle energy, select those with the heaviest bullet. They'll offer both high energy and the greatest available momentum. If you're using a round with marginal energy, use a calculator such as that linked above to determine the cartridge with the greatest momentum. You'll need it!
  5. Find out which of the cartridges you identified in Step 4 are used by local, or State, or national police forces (we discussed the reason for this in Part 2 of this series). One of the latter should be your chosen carry load, if possible. If your chosen handgun is in a caliber or cartridge that isn't used by police forces, then select the best load identified in Step 4 and carry that. (Don't forget the 200-round reliability test for it we mentioned in Part 2!)

My personal 'rule of thumb' is that, in a primary handgun, I want muzzle energy of not less than 350-400 foot-pounds, plus acceptable bullet momentum to provide penetration. Smaller, lighter calibers will not fit those criteria, of course. In a secondary handgun (i.e. a smaller, lightweight handgun carried for backup purposes, or slipped into a pocket when I can't carry a full-sized handgun for some reason), I'll lower my standards to 200-300 foot-pounds - but never less than that. I also want bullet momentum greater than 15 lb/ft. per second, and preferably over 20. I simply don't trust lower-powered rounds! I've seen too many gunfights, where smaller, less powerful rounds failed to get the job done, to be willing to trust my life to them. (Eighteen years of extremely violent civil unrest provided more than enough such opportunities, regrettably . . . ) This means that the smallest defensive cartridges I'm willing to carry are .38 Special +P in revolvers, or 9mm. Parabellum +P or +P+ in pistols. At the time of writing, my ammo locker contains the following selected loads, one of which is always in the gun at my side:

You'll note that all of the cartridges shown above should be pretty adequate performers. I don't get hung up about caliber: I look for sufficient penetration, with enough energy to dump. For an interesting comparison of the performance of these calibers (and more) in ballistic gelatin, as well as a very useful summary of their suitability for defensive use, see here.

On the other hand, I've trained many disabled shooters who can't handle the recoil of anything bigger or more powerful than a .22LR! I'm also partly disabled myself, and therefore can't handle the recoil of .45 ACP (my favorite defensive cartridge) as well as I used to. It's much harder for me to put aimed, accurate, rapid fire on target with it now: so I find myself forced to carry rounds with less recoil, whether I like it or not. (I don't!) One does the best one can with what one can use effectively. If, one day, due to physical deterioration, I can no longer control a round with my desired energy and momentum levels, I guess I'll just have to practice harder with a smaller cartridge, to ensure I can put it where I want it at all times. Accurate bullet placement does more for 'stopping power' than anything else.

Accuracy is essential, but so is choosing the correct point of aim - and changing it when necessary! Unquestionably, for most defensive encounters, we should begin by aiming at the largest available target (the torso), trying to take out the heart and major blood vessels: but what if this doesn't work fast enough? I've never forgotten one ghastly incident in South Africa. An acquaintance was attacked by a machete-wielding man who was hopped-up on marijuana and alcohol. The defender drew his 9mm. Browning Hi-Power pistol and put no less than six Federal 9BP hollow point bullets into a five-inch circle in the chest of the attacker. The bullets performed as intended, mushrooming impressively and penetrating adequately. They shredded the attacker's heart - this was proven at autopsy - but they didn't stop him immediately. He had enough oxygen in his brain to close the (short) distance to my acquaintance and swing a wild blow with his machete, which chopped open his victim's head, slicing deep into his brain. Both the attacker and the defender died at the scene while waiting for medical attention.

If my acquaintance had only shifted his point of aim after two or three shots (by which time it should have been clear to him that they weren't producing the desired result - stopping the attack), and put the remaining three rounds into the "target triangle" in the attacker's head (see the first image above), things might have been very different. After all, the attacker was getting closer all the time, making that small target a practical proposition for a skilled shooter (as my acquaintance was). The three people with him (including myself) were all busy dealing with other problems at the time; so we weren't able to add our fire to his, which might also have made a difference.

I had the dreadful task of informing his wife, later that night, that her husband was dead. I couldn't - I never did - tell her that if only he'd switched his point of aim, he might still have been alive . . . He'd been trained to always shoot at the center of mass. His instructors had never bothered to tell him that sometimes, that wouldn't be enough, necessitating a shift in the point of aim; and they hadn't trained him to move while shooting, creating more distance between himself and an attacker and/or avoiding his blows. I'd received the same training: but after witnessing that incident, you can bet I added those missing elements to my regular range sessions, and passed them on in time to those I taught!

Shooting is a perishable skill. It must be practiced regularly if it's to be mastered and retained. There's no point in buying a worthwhile defensive handgun, selecting an effective cartridge for it, and walking around with it on your hip, if you don't know how to hit the proverbial barn from the inside! I strongly recommend attending at least one introductory training course, such as those offered by the NRA at many local shooting ranges. I further recommend attending a course such as Massad Ayoob's MAG-40, which offers invaluable insights into the psychology of a deadly force encounter, interaction with the police, etc., as well as range time with your handgun. (I've taken three courses from Mas Ayoob, and regard them as the finest of their kind available to private citizens. They're not so much 'shooting courses' as instruction on 'managing the lethal threat environment', which goes far beyond the mere mechanics of getting rounds on target. Highly recommended.)

I hope this discussion has shown clearly that there's no such thing as 'stopping power'. There are larger and smaller bullets, with more or less energy; more or less momentum; and greater or lesser efficiency and effectiveness than one another. Choose the best bullet you can in a caliber you can handle, and train to deal with a threat if it should arise. That'll do far more for your survival than depending on some super-dooper, magnum-blaster, (allegedly) felon-shredding bullet that someone advertises as "the ultimate in STOPPING POWER!!!" Needless to say, they're lying.



Jerry said...


This is excellent stuff. Is there any way that you can create a pdf containing all three parts and make it available for download? Thanks.

Peter said...

Jerry, I'll look into that. I'd have to have a place where it could be hosted, of course . . . Blogger doesn't offer that facility.

Glen said...

One very minor point about shooting the head. The sight picture which contains a human face lingers for a very long time. This is a small but good reason to concentrate on the front sight, and the upper chest of your target.

Peter said...

Glen: Yes, it does, doesn't it?


davidc said...

Very informative article, thank you !

Old NFO said...

Well done Peter, and it ALL comes down to shot placement in the end...

Morris said...

Peter, a suggestion for making a PDF file sharable. One of the sites such as might be what you need. You can upload a file and immediately get a share link for same for people to download from. A personal account is free and has 5 gb available.

Kerry said...

We note with amusement your neglect to highlight the fantastic stopping power of the .380 as featured on films and TV. How could you be so negligent. Heh.

Anonymous said...

Really great! One thing: You say it is difficult for you to handle recoil. As much as I love revolvers for their reliability, pistols seem to have weaker recoil due to the large mass of the barrel, travelling back. Did you ever shoot a Glock? Almost no recoil, still reasonably powerful.

Peter said...

@Anonymous at 9.48 PM: Yes, I shoot a Glock. They work well.

ParaPacem said...

This really is a good and well thought out series. One of my favorite parts is - " therefore can't handle the recoil of .45 ACP (my favorite defensive cartridge) as well as I used to. It's much harder for me to put aimed, accurate, rapid fire on target with it now: so I find myself forced to carry rounds with less recoil, whether I like it or not. (I don't!)"

I also am one of those who, four decades ago, was in love with my 1911s and 12 gauges,and would not back away from heavy hitters... but as the inevitable changes to the joints and tissues come with the years, those options are no longer practical, so I have to be content with putting 12 out of 15 rounds of 9 into a pie plate area at 25 yards, or using a 308 instead of a 338 Lapua.

Even so - my experience has been that most 'bad guys' unless totally out of their heads, do not desire to have copper and lead holes punched into their vitals if they can avoid it.

Thanks for the great work.