The truth about “stopping power” – Anatomy First

“Stopping power.” How many times have you heard that ridiculous phrase? “You have to use a [insert caliber/breed/style] round if you want a one-stop shot!” Sure, science tells us that a fully oxygenated brain can keep the body moving for several seconds after the heart is destroyed, but what is science compared to conventional wisdom and urban myth? Today COWAN! is going to discuss this nebulous, even insipid thing called stopping power and give you some insight on the truth behind it. As always, we welcome input (including disagreement) from those of you who are serious about the noble profession of arms. We know this is going to stir up a debate. Let’s strive for dialectic disputation. Mad Duo

Grunts: dialectic and disputation – you’re welcome.

Stopping Power Realities: Anatomy first – and Ambulation After Death


Authors Note: This is long because it has to be.  As with some other topics, I felt it beneficial to be as specific as possible and cover all the major topics. The idea of “stopping power” is so pervasive in the firearms community that it has become laden with myths, misinformation, misconceptions and outright lies. Because of this, I felt like this article needed to be written.

None of the information contained herein is previously uknown or new. Much has been covered. Many arguments were put to bed (or should have been put to bed) by the FBI’s 1989 Handgun Wounding Factors and Effectiveness Report. Regrettably, this information is only found when it is actually looked for. Sometimes it’s much easier to take a trusted word , or go with a fact that sound reasonable without doing any due diligence to check it. Perhaps this is the sort of article that someone should write every few years, or few months, in order to remove the myths and misinformation from the self-defense community.   In any event, I hope you guys enjoy it. If you learn one thing or correct one myth, it was worth the time.

In order to measure, we must be able to quantify.

That’s the sentence that throws many suppositions, deductions and handpicked data for ‘this caliber over that’ right out the window when it comes to stopping power. I know going into this that I won’t change minds that refuse to change; those who hold an emotional argument or opinion are not often dissuaded with facts. So just to get things out of the way I’m going to put everyone on the same footing:   There is no definable scale, system of measurement or reliable and impartial data to support the idea of stopping power. There is only opinion and subjective facts.

No gunfight has ever occurred under scientific controls. No two gunfights have ever been or will ever be the same. We can measure the performance of firearms, the expansion of rounds in ballistic gel (which is a tissue substitute, not a body substitute and ballistic gel is closer to the density of muscle tissue than body tissue) and even stacks of wet phone books if you like. We cannot, however, rely on this information to definitely prove how a round will act against the human body. We can get an idea of performance, but not hard facts of it. Every shooting is unique; conditions, clothing, stimulants, body weight, distance, barriers, movement, ammunition, point of aim, point of impact, rate over movement/rotation of the body as the round strikes, psycho-physiological factors and many other variables make an accurate quantification impossible.

Well, what about an average then? We cannot even establish a reliable average because in order to do so, we would need quantifiable data from each type of defensive round. That would mean that every single possible variable was accounted for. This is an improbability so great it is functionally impossible.

My opinion is that the conversation has always had the wrong focus; instead of talking about what [X] bullet does or doesn’t do, we should really be talking about where to put those bullets.

Advocates of one round over another have their motivations, some justified, some ridiculous; sometimes they advocate based on personal experience, sometimes on advice, other times on reading favorable data and occasionally on pure hyperbole. Every round has succeeded. Every round has failed. Depending on what light you want to show a round in, results can be cherry picked to suit your opinion. Consider the following.

On August 8th of 2008 Skokie, Illinois police officer Tim Gramins was tailing a bank robbery suspect to initiate a stop when the suspect stopped suddenly, exited the vehicle and attacked. Gramins and the suspect Maddox exchanged gunfire in an extreme close quarter fight. When it was over Maddox had been hit 17 times before going down, including three fatal hits to the head. Officer Gramins service weapon was chambered in .45, Duty round unknown. 1

In a shooting that has become known as the Peter Soulis Incident2, Jacksonville, Florida officer Pete Soulis made contact with a suspicious driver, Joseph McGrotha, at a gas station in October of 1997. McGrotha was initially compliant, although this didn’t last. McGrotha produced a 9mm handgun, firing one round into Soulis’ chest (it was stopped by his armor).   Before it was over Soulis was shot three more times while shooting McGrotha 22 times, 17 of which were described as “center mass.”   It would take McGrotha as long as 4 minutes to die after the last shot was fired. Officer Soulis service weapon was chambered in .40 S&W, Winchester Ranger SXT rounds.

In August of 2010, NYPD Officers opened fire on an armed man they believed to be leveling a weapon against them. Angel Alvarez was hit 23 times and subsequently made a full recovery. Luis Soto, also involved in the shooting, was stuck 5 times and died at the scene. All service weapons involved were chambered in 9mm, loaded with Speer Gold Dot 124 grain3.

There are three examples, one for each caliber, of a round failing to stop the threat in short order (or at all) and as an added bonus, an example of both the less than ideal andidealperformance for the 9mm round all in the same shooting.

What does this tell us? Be careful of sampled examples.

Every round on the market has its detractors and advocates, some of these people are using personal experiences, outdated information, incorrect information or a small handful of examples to support their choice in round.   The fact is and will always remain that there is as much evidence for and there is against a round based on its performance because of the thousands and thousands of variables that shape each use of force. No one round can be quantified based on selected data because there is no uniformity in the shootings. We can have anecdotal results, anecdotal performance but nothing approaching definitive.   We like to talk about the round because it’s tangible, it’s something we can see for ourselves and test in our own ways. This is not the case with self-defense shooting.

I’ve always been mildly surprised by a lack of anatomy knowledge when it comes to shooting discussions. One doesn’t have to be a doctor to know the basics of the human body and where it is most vulnerable, yet there seems to be either a lack of interest in or a failure to realize the importance of this information. I want to know everything I can about my enemy. As he is very likely to be the same species as myself, I have spent a lot of time studying people and the best ways to make them stop doing things that cause people to be shot in the first place. That is time well invested. When the conversation comes up, I have heard some very ridiculous assumptions about the human body and how easy it is to stop someone. I have also heard many times that once someone goes down, they are out of the fight. Down is two things; gravity and medical/psychological failure. One of those is a constant, the other may be quite temporary.

Part of the problem is in the way we train and the way we practice. Despite a growing number of anatomy targets on the market, most shooting is still done on score-system silhouettes that are 2-dimensional paper. As I’ve said in the past, these targets present a best case scenario of a squared target and ignore the more realistic aspects of the human body, the most important being that a real body is three dimensional.

Ammo stopping power vs anatomy Cowan Breach Bang Clear 3D target

Compounding this is the already-mentioned lack of anatomy training in professional courses. I have attended a number of professional schools and courses (including Army basic [infantry], two law enforcement academies, NRA LE instructor development courses and a number of private and LE focused instructional classes). None of them offered a block on anatomy. Maybe because it was so long ago?

I went through basic training in 1999. Modern medical knowledge is just a bit older than that.

Sure, instructors will bring up facts about anatomy here and there. Sometimes they are right, sometimes they are wrong but they hardly ever offered anatomy as a primary focus of instruction. Treating it as a secondary (or even tertiary) topic it fails to highlight the subject’s importance. I made cursory look around the internet, searching for “defensive handgun training” and “defensive rifle training”. Of the top 10 results for each search via Google, not a single mentioned anatomy or physiology as part of their curriculum. Sure, you can type in “tactical anatomy” or “threat anatomy” and find a medical class geared towards teaching people where to put bullets in the human body (or how to plug up embarrassing and undesired holes), but it isn’t on the first page; it’s not even on the fifth. A basic understanding of anatomy is not an advanced skill and shouldn’t be treated as such, yet it’s just not up for discussion in a lot of conversations.

Maybe the shooting community is so indoctrinated to the idea of shooting paper that they don’t know to ask for it?

Bullets however – people love to talk about bullets. Bullets are tangible, they reaffirm our choice in firearm by brand and model. Caliber choice sometimes even defines the ‘type of shooter’ someone is. This is a world where a shocking number of people still think the impact of a bullet can, of its own force, knock someone down, don’t know the physical location of the heart in their own chest and think that shooting someone in the pelvis is some kind of magic incapacitation. Sadly these same people can probably describe the massive awesomeness of their round of choice, and maybe even how a double tap is all you need.

Ammo stopping power vs anatomy Cowan Breach Bang Clear anatomy target

The performance of humanity.

How many rounds does it take to stop a threat? The only correct answer to this questionis “as many as it takes to gain compliance, surrender or incapacitation.”

That is the only correct answer.

Let’s de-sterilize that word incapacitation: Incapacitation in our context means death, unconsciousness due to blood loss or central nervous failure resulting in the loss of bodily control. It does not mean on the ground unless on the ground includes one of those three conditions.

How long does it take to truly incapacitate someone? The only guaranteed instantaneous incapacitation is in the head; the brainstem. Every other location of the body is a delayed incapacitation at best. What about shooting someone in the heart? Well, the heart is a muscle and outside of large caliber rifles, bullets are not big enough to totally explode the heart. Assuming that a round fired from a normal defensive weapon could totally explode the heart, your bad guy still has time to fight because his brain and limbs will have enough oxygenated blood in them to allow him to fight. Cutting all blood flow to the brain, your bad guy has up to 10 seconds until unconsciousness and approximately 20 seconds until total electrical failure4. That’s a long time – especially if that person is trying to “incapacitate” you.

What about massive bleeding? Since it’s (very damn) rare to totally explode the heart or totally sever major arteries, and because the body acts as a barrier to blood loss, the loss of blood will have to reach about the 30%-40% range before incapacitation can be expected. In order to cause severe blood loss, we have to hit major organs and arteries. The average resting cardiac output is 5 liters a minute5 (for an example 154 pound man); imagining a major hemorrhaging (level IV) from a sufficient diameter wound, it will take our mope at least 20 seconds to lose 40% blood volume. Remember that even once that happens we have the above mentioned loss of oxygenated blood to the brain to confront.

Blood does not flow at this rate because cardiac output does not equal bleed rate from point of injury. As blood loss increases, pressure drops, though cardiac output can be expected to increase under stress. These two facts complicate each other, making a prediction difficult. Even going with the best case scenario (outside of a brainstem hit), incapacitation is going to take time and that time is dependent on how well you shoot, how deep the rounds penetrate and what they hit inside the body. Even suffering a fatal wound, your bad guy can continue to fight until system failure; Ambulation after Death is common and should be expected (seen in Tim Gramins shooting earlier in the article).

If this seems more complicated than simply shooting score rings or color shapes, well gosh, that’s because it is.

My personal goal is that every student leave my classes with a greater appreciation for realistic shooting and with that a greater attention to where bullets should go. We have very limited control over how our bad guy decides to move; the human body twists and contorts in frustrating ways and this makes your “center mass” shooting a severe difficulty. “Center mass” is the center point of what we are aiming at, it is not center of the chest. This is yet another belief passed down from the ideal conditions that 2D targets give us.

So what is vulnerable? Where is it in the body? What’s the best way to break it?

Ammo stopping power vs anatomy Cowan Breach Bang Clear 3D head target

Knowledgeable Introduction of Trauma

We have three general zones on the human body for the sake of shooting; head, chest and pelvis. I list these in general order of importance.

The head is where the off switch is located. The brain is our software; it controls everything and is dependent on a sort of harmony to work effectively.   That harmony is easily disrupted by bullets.

The brain is our ideal target if distance, skill and circumstances allow for the shot. People shot in the head have a shockingly low survival/recuperation rate compare to those shot in other places. Despite its size relative to the rest of the body, the head is a rather large point of aim. It’s not a realistic point of aim in many circumstances but it must be considered far more often than it is currently.   The brainstem (highlighted) is an ideal desired point of impact. Outside of that we have the cranial vault, which contains the brain. A strike to the brainstem results in flaccid paralysis and CNS failure, a single strike to the brain may not result in instant incapacitation, which is one reason repeated rounds until verified failure is preferable.

The brain is protected by the skull and the skull is made up of a collection of dense bones that are resistant to trauma. One reason given for not targeting the head is usually that the skull will deflect bullets; this is absolutely true, it can. This reason is often based up with an example or two of a bullet failing to penetrate the skull. The response to this anecdotal evidence should be what about all the times where the bullet penetrated the skull? That is far more common and well within a reasonable expectation for common self-defense calibers6. It’s also worth noting that ballistic trauma to the head results in fatalities 80% of the time7.

Ammo stopping power vs anatomy Cowan Breach Bang Clear skull vitals 2 Ammo stopping power vs anatomy Cowan Breach Bang Clear skull vitals 1

So much for those anecdotal “won’t penetrate the skull” stories, huh?

The chest or High Thoracic Cavity is where most firearms training is focused. It’s a large target, gives us a good margin of error for accuracy and contains a number of organs and vessels pretty important to life function. There is no off switch in the chest; no instant incapacitation, just a place where we are most likely to induce heavy blood loss. The heart, lungs, pulmonary veins and arteries, as well as the origin point of all arteries are located in the chest. Major bone mass is predominantly the ribs, which are resistant to blunt force trauma but do not do such a good job at protecting the internal organs from ballistic trauma. The heart lays more-or-less center of the chest and is usually described as being the size of an adult fist, which is usually true. As a point of aim it’s a difficult target, but the heart is the vascular train station for all the blood in the body and because of that, the surrounding area is almost totally vital and vulnerable tissue.

The Aorta and Pulmonary arteries are major traffickers, with many smaller arteries in the same area. All things considered, a gunshot wound to a major artery such as the aorta would be more traumatic than one to the heart as the heart is a muscle, not nearly as elastic or prone to tearing as arterial veins. Of course we already know that relying on blood loss means its going to take time for our bad guy to go down and stay down, so we want to put as many holes in him as we can while he’s still a threat to speed that process along. By far, the most common trauma associated with targeting of the chest is injuries to the lungs is a collapsed lung (pneumothorax). Chest injuries in general often result in hemothorax, which is when the body creates a barrier to blood loss and it collects in the chest cavity.

Fatality/incapacitation rates outside of direct cardiac injury are to inconsistent to predict or get a percentage on, however when it comes to cardiac injuries medical professionals are pretty direct in their assessment:

“Cardiac injuries are rare in patients who reach the hospital because these injuries are often lethal at the scene.” 8

Targeting the chest means that incapacitation is going to take time, though knowledgeable targeting of the most vital areas will greatly help reduce that time.

Ammo stopping power vs anatomy Cowan Breach Bang Clear chest vitals 3 Ammo stopping power vs anatomy Cowan Breach Bang Clear chest vitals 2 Ammo stopping power vs anatomy Cowan Breach Bang Clear chest vitals 1

The last ideal area of the body to target is the lateral pelvis. Also called the pelvic girdle, this area is comprised of very dense bones designed to support weight, resist omnidirectional forces and assist in the generation of movement.

The number of vital organs located in this area is zero, as in none. The pelvic girdle has seen a resurgence in popularity as a place to intentionally target. Some even saying they would shoot here before trying for the chest (which makes zero sense). The pelvic area does contain arteries. Unfortunately those are small targets and very, very few people can even point to their general location, let alone target one.

The aorta enters the pelvic region, branches out into the iliac arteries which move through the pelvic girdle to become the femoral arteries, essentially an inverted “y.” While it’s very true that ballistic trauma to this area can cause immobilization via the breaking and shattering of bones, it is highly unlikely to cause incapacitation in a reasonable amount of time. One of the most recent studies into pelvic gunshot trauma found that out of over 2,800 gunshot wound related patients, 42 had suffered trauma to the pelvic region, only 18 of those resulted in fractures to the Ilium and only 7 of those actually required surgery. 9

That is not exactly reassuring.

Ammo stopping power vs anatomy Cowan Breach Bang Clear pelvic vitals Ammo stopping power vs anatomy Cowan Breach Bang Clear pelvic bone

The pelvis is a viable target barring a better one to shoot at, but it’s not the magical incapacitation button some people sell it as. My feeling is that the popularity of pelvic shooting is because on the vast majority of ranges across the US, the pelvis is the point of aim when practicing hip shooting because the range will not allow higher angle shots. It certainly isn’t because there is a wealth of examples of pelvic incapacitations, because those examples are very rare. I don’t discount the pelvis as a place to shoot, though I would only choose it if other areas of the body were not available to me( or if it was the first stop on my way up the body). Any other methodology is snake oil. Dirty, nasty snake oil.

The science of the bullet.

This argument has beaten so many horses that the ASPCA wants us to use a different idiom. Caliber, it is said, is not as important as round placement and penetration. This is absolutely true, though it does detract from the fact that the damage the bullet causes is also important.

When it comes to incapacitation, we need placement, penetration, permanent cavity, temporary cavity (uncommon to a notable degree in handguns) and fragmentation (either of the bullet or secondaries such as bone, also uncommon in handguns). All rounds will provide penetration and permanent cavity, though the effectiveness varies based on the physics of the round and the very uncontrollable variables of shooting people.

Penetration is by far the most important factor (if only by a margin) because a superficial cavity, no matter its diameter, may not penetrate deep enough to cause incapacitating injuries. If a bullet expanded to the size of a soup can on impact but only penetrated 2”-3” into the body, its effectiveness would be minimal. I know that is a gross exaggeration but it underlines a problem in thinking about the damage a bullet could potentially cause without first considering this first – will it get anywhere there are things worth damaging?

Ammo stopping power vs anatomy Cowan Breach Bang Clear 3D target

Because of this (and because of physics) a bullet’s speed has a greater impact on the amount of damage it causes than its size. Speed is what ultimately will provide the energy needed for greater penetration.

“The amount of kinetic energy delivered by the hitting body (projectile, bullet, shrapnel…) at the time of impact depends mainly upon the squared velocity (E = ½MV2) and in a lesser degree to the projectile body mass.” 10

The kinetic energy of the bullet is generated by its velocity and mass (K=1/2 MV2- K= kinetic energy, m= mass of the bullet, and v= velocity of the bullet). Kinetic energy is what we rely on for terminal ballistics, which is usually tested in ballistic gelatin as a stand in for the human body, as opposed to an actual human body for obvious reasons. Ballistic gel must be carefully calibrated to best replicate the human body and because calibration is often not known, not enforced or not considered when some people publish/film results of this or that round, we tend to get bad data. 11

Just because a round appears to perform well in a block of gel does not mean it will do the same against the human body. It’s a science, and unfortunately isn’t often treated that way.

When a bullet strikes, it creates a crush cavity, crushing (centrifugally) the tissue in its path. The speed of the round, paired with its expansion (if any) creates a small temporary wound cavity in handguns and other lower velocity rounds. The crush mechanism, the physical nature of the bullet destroying tissue in its path is by far the largest factor in wound/round effectiveness12. This is where the debate always lies; smaller, faster rounds versus bigger, slower rounds. Is the 9mm better than the .45? Yes. No. Depends.   Maybe.

This is why we can’t quantify, because we cannot accurately measure.

I use a 9mm because it offers less resistance to success. It offers flatter recoil, larger capacity per magazine by gun size and a round known for its penetrating capabilities.   My choice is as much preference as it is performance; this is what most people tend to base their carry round on. Those of us who have direct experience with a round’s performance on the human body are not as common as those who do not, which is why good information and realistic expectations are so important. What’s more important is looking at the best way to cause ideal results once you possess that information. All popular calibers today can produce those ideal results provided you do your part.

Your part consists of realistic knowledge of how best to destroy the parts of the human body critical for a bad guy to keep doing whatever it is he’s doing that causes you to use force against him. It’s about effectively shooting them to the ground and making sure they stay there. Paper is a measure of mechanical skill; it’s not as effective when it comes to real life. Don’t stop with this article; learn as much about the body as you do about anything else of great importance.

It’s time to stop talking hardware and start talking about breaking the bad guy’s software. The best way to break his software is to remove its ability to function.

COWAN! profile pic 1About the Author: Aaron (Breach Bang COWAN!) is an idiot savant of the tactical variety from a little place we like to call Hotlanta (though apparently no one from down there calls it that). COWAN! is the Lead Instructor and HMFIC of program development for Sage Dynamics who believes every article should be roughly the equivalent of a doctoral thesis. To call him thorough would be to damn him with faint praise. We call him COWAN! because anything in all caps with an exclamation point after it must be awesome. A former infantryman turned PSC contractor and LEO, COWAN! has served in several SWAT and training billets. His company, Sage Dynamics, is a reality-focused firearms and tactics training company that provides practical instruction for the civilian, police and military professional. An identical twin whose brother went on to become Agent 47, COWAN! is the author of the novel Rushing Winter and the designated fluffer on the set of numerous training videos, including the really good ones here.

COWAN! profile pic 4


1 Shots Fired: Skokie, Illinois 08/25/2008 Police Magazine online article

2 Shooter’s motive remains mystery 10/21/97 The Florida Times-Union, online article. Officer Down: The Peter Soulis Incident, article (2008)

3 Jury Doesn’t Indict Man in Police Shooting, The New York Times, (2011) Wound Expert Says NYPD’s Firepower In Harlem Was Sufficient, (2010)

4 The Pathophysiology of Brain Ischemia Dr. Marcus Raichle Neurological Progress (1983)

5 Pharmacology & Physiology in Anesthetic Practice, Robert K. Stoelting

6 When the Bullet Hits the Bone: Patterns in Gunshot Trauma to the Infracrainal Skeleton, Katharine A. Chapman, B.A. (2007) Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques, Vincent J.M. DiMaio (1985) Characteristics of Gunshot Wounds to the Skull, Faculté de Médecine de Nice, Laboratoire de Médecine Légale, France, Dr. G. Quatrehomme (1999)

7 Predictors of mortality in severely head-injured patients with civilian gunshot wounds: a report from the NIH Traumatic Coma Data Bank. Dr. EF Aldrich

8 A civilian perspective on ballistic trauma and gunshot injuries, Dr. Philipp Lichte (2010)

9 Civilian gunshot wounds of the hip and pelvis, Dr. MJ Bartkiw, Department of Orthopedic Surgery, Detroit Receiving Hospital and University Health Center

10 Whats Wrong With Wound Ballistic Data, and Why, Dr. M.L. Fackler (1987), Undeniable Evidence, Dr. M.L. Fackler,Wound Ballistics Review; International Wound Ballistics Association (1999)

11 Wound Ballistics and Tissue Damage, Nimrod Rozen and Israel Dudkiewicz

12 Handgun Wounding Factors and Effectiveness, FBI Academy Firearms Training Unit, SA Patrick (1989)

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