The Myth of Knockdown Power
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Old 06-09-2010, 06:57 PM   #1
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Default The Myth of Knockdown Power

The truth about handgun knockdown power
11/19/2008

P1 Exclusive: The truth about handgun knockdown power
By Commander Jeffry L. Johnson
Long Beach Police Dept., Detective Division
Special contributor to PoliceOne

There is undoubtedly no other myth more perpetuated and closely held (even now) by many law enforcement professionals than what I have previously referred to as the “Demonstrative Bullet Fallacy,” or in plainer terms, the idea that any handgun of any caliber has “knockdown power,” in that the sheer size and force of the bullet can knock a person down. Closely related is the myth that bullet size — rather than shot placement — can determine or ensure a “one shot stop.” Both are inaccurate, unscientific, and dangerous, and have no place in the training of law enforcement professionals.
Not that any of this is new information. This fact has been generally known for about six hundred years or so. Notable intellects such as DaVinci, Galileo, Newton, Francis Bacon, and Leonard Euler all studied physics and ballistics, as did many others. It was Newton’s research that led Benjamin Robbins to invent the ballistic pendulum in 1740 (the first device to measure bullet velocity).

There is no mystery here — the truth has been documented time and again. So how is it that we still don’t get it? One word: Hollywood.

Ever since Dirty Harry came along with his .44 Magnum hand-cannon, when someone gets shot in the movies or on TV (and don’t forget video games) two things happen: 1) the victim is thrown back convulsively, through windows, off balconies, etc. and 2) there will immediately emerge a geyser of blood spewing forth from the wound, leaving no doubt that this person has been shot, and pinpointing exactly where the bullet has struck.
Many firearm and shooting magazines picked up on the idea as well, discussing and propagating the pseudo-scientific idea of handgun “knockdown power” and “one shot stopping power.”

The Truth

The Federal Bureau of Investigation Firearms Training Unit published a concise yet insightful report that speaks directly to this issue of firearm wounding ballistics and the misconceptions that have surrounded this area.
These so called [knockdown power] studies are further promoted as being somehow better and more valid than the work being done by trained researchers, surgeons and forensic labs. They disparage laboratory stuff, claiming that the “street” is the real laboratory and their collection of results from the street is the real measure of caliber effectiveness, as interpreted by them, of course. Yet their data from the street is collected haphazardly, lacking scientific method and controls, with no noticeable attempt to verify the less than reliable accounts of the participants with actual investigative or forensic reports. Cases are subjectively selected (how many are not included because they do not fit the assumptions made?). The numbers of cases cited are statistically meaningless, and the underlying assumptions upon which the collection of information and its interpretation are based are themselves based on myths such as knockdown power, energy transfer, hydrostatic shock, or the temporary cavity methodology of flawed work such as RII. (1)

The truth is, the whole idea of handgun knockdown power is a myth. It simply doesn’t work that way. The FBI report further clarifies:
A bullet simply cannot knock a man down. If it had the energy to do so, then equal energy would be applied against the shooter and he too would be knocked down. This is simple physics, and has been known for hundreds of years. The amount of energy deposited in the body by a bullet is approximately equivalent to being hit with a baseball. Tissue damage is the only physical link to incapacitation within the desired time frame, i.e., instantaneously. (2)

The report cites previous studies that have calculated bullet velocities and impact power, concluding that the “stopping power” of a 9mm bullet at muzzle velocity is equal to a one-pound weight being dropped from the height of six feet. A .45 ACP (45 auto) bullet impact would equal that same object dropped from 11.4 feet. That is a far cry from what Hollywood would have us believe, and actually flies in the face of what even many in law enforcement have come to mistakenly believe.

The FBI report also emphasizes that unless the bullet destroys or damages the central nervous system (i.e., brain or upper spinal cord), incapacitation of the subject can take a long time, seemingly longer if one is engaged in a firefight.

Failing a hit to the central nervous system, massive bleeding from holes in the heart or major blood vessels of the torso, causing circulatory collapse is the only other way to force incapacitation upon an adversary, and this takes time. For example, there is sufficient oxygen within the brain to support full, voluntary action for 10-15 seconds after the heart has been destroyed. (3)
More often than not, an officer firing at a suspect will not immediately know if he or she has even struck the target. The physics are such that the body will rarely involuntarily move or jerk, and usually there is no noticeable spewing of blood or surface tearing of tissue. Often there is no blood whatsoever. (4) That is why military surgeons and emergency room physicians take great time and pains to carefully examine gunshot victims for any additional small holes. Often that is the only indication the person has been shot.

Personal Experience

But let’s be real here. I can cite numerous additional academic and scientific sources that support this article, but I know how cops think. We’re not always the most trustful of academics, especially when it comes to our street survival. So let me add my own personal experience to the data. Please allow me to go beyond the cold facts and share with you why I know what I’m telling you is the truth.

In the mid-1980s I was involved in my first shooting as a police officer. But to give the story context, I must go back to 1982 when I graduated from the Long Beach Police Academy. The first thing I was told by experienced training officers I trusted and looked up to, was to “get rid of that pea-shooter 38 they issued you and buy a real gun with some knockdown power!” Although we were issued .38 caliber revolvers, we were authorized to carry a number of different caliber weapons on duty, the largest of which was the 45 Long Colt.

The .45 Long Colt round next to the diminutive 9 millimeter.

Imagine my surprise when I was confronted by a suspect armed with a shotgun in a dark alley and my Long Colt didn’t live up to its billing. I fired five rounds at the suspect. It wasn’t until I fired my last shot — intentionally aimed at his head — that he went down. I can’t begin to relate to you the surprise and horror I felt when there was absolutely no outward indication I was hitting my target. It was the kind of situation cops have nightmares about.
What actually happened? I fired five rounds at a distance of about twelve feet. The first one missed completely. The second struck his upper leg and broke his femur. The third struck him in the shoulder/chest. The fourth round hit him dead center—in the heart. And of course, the fifth was a headshot. Three of the five rounds created fatal wounds, though only one had immediate results.

Needless to say, I was pretty shaken by the whole thing. Not by the morality of what I’d done; the suspect had already fired at a bystander and taken a hostage earlier. He was also high on PCP. That wasn’t my inner struggle. What shook me was how unprepared I felt; how totally off guard I was taken by what occurred. No one ever told me it would be like that. The reality was contrary to everything I thought I knew about deadly force.
That experience more than any research or study is the reason is why I am writing this article. Police officers risk getting into shootings every day; we need to know the dynamics of how a shooting incident may unfold. It will affect our equipment, tactics, and most important, our mindset. We need to know that rarely will one shot incapacitate an assailant. We further need to be able to explain this when our fellow officers are involved in shootings where multiple shots are fired. The public honestly believes it’s like the movies. Why would we ever need to fire twenty or thirty rounds to subdue an armed suspect? Problem is we can’t teach it or explain it until we understand it ourselves. (5)

Footnotes:
1. Patrick, Urey W., Federal Bureau of Investigation, Firearms Training Unit, “Handgun Wounding Factors and Effectiveness,” p.13. (1989).
2. Ibid., p.9.
3. Ibid., p. 8.
4. Newgard, Ken, MD, “The Physiological Effects of Handgun Bullets: The Mechanisms of Wounding and Incapacitation” (1992).
5. For you visual learners still unconvinced, I highly recommend viewing the Discovery Channel MythBusters segment, “Blown Away,” (Brown Note Episode, Second Season), where the knockdown power myth is visually and scientifically debunked once and for all.
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Old 06-09-2010, 07:51 PM   #2
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Originally Posted by KalashnikovJosh View Post
The truth about handgun knockdown power
11/19/2008

P1 Exclusive: The truth about handgun knockdown power
By Commander Jeffry L. Johnson
Long Beach Police Dept., Detective Division
Special contributor to PoliceOne

There is undoubtedly no other myth more perpetuated and closely held (even now) by many law enforcement professionals than what I have previously referred to as the “Demonstrative Bullet Fallacy,” or in plainer terms, the idea that any handgun of any caliber has “knockdown power,” in that the sheer size and force of the bullet can knock a person down. Closely related is the myth that bullet size — rather than shot placement — can determine or ensure a “one shot stop.” Both are inaccurate, unscientific, and dangerous, and have no place in the training of law enforcement professionals.
Not that any of this is new information. This fact has been generally known for about six hundred years or so. Notable intellects such as DaVinci, Galileo, Newton, Francis Bacon, and Leonard Euler all studied physics and ballistics, as did many others. It was Newton’s research that led Benjamin Robbins to invent the ballistic pendulum in 1740 (the first device to measure bullet velocity).

There is no mystery here — the truth has been documented time and again. So how is it that we still don’t get it? One word: Hollywood.

Ever since Dirty Harry came along with his .44 Magnum hand-cannon, when someone gets shot in the movies or on TV (and don’t forget video games) two things happen: 1) the victim is thrown back convulsively, through windows, off balconies, etc. and 2) there will immediately emerge a geyser of blood spewing forth from the wound, leaving no doubt that this person has been shot, and pinpointing exactly where the bullet has struck.
Many firearm and shooting magazines picked up on the idea as well, discussing and propagating the pseudo-scientific idea of handgun “knockdown power” and “one shot stopping power.”

The Truth

The Federal Bureau of Investigation Firearms Training Unit published a concise yet insightful report that speaks directly to this issue of firearm wounding ballistics and the misconceptions that have surrounded this area.
These so called [knockdown power] studies are further promoted as being somehow better and more valid than the work being done by trained researchers, surgeons and forensic labs. They disparage laboratory stuff, claiming that the “street” is the real laboratory and their collection of results from the street is the real measure of caliber effectiveness, as interpreted by them, of course. Yet their data from the street is collected haphazardly, lacking scientific method and controls, with no noticeable attempt to verify the less than reliable accounts of the participants with actual investigative or forensic reports. Cases are subjectively selected (how many are not included because they do not fit the assumptions made?). The numbers of cases cited are statistically meaningless, and the underlying assumptions upon which the collection of information and its interpretation are based are themselves based on myths such as knockdown power, energy transfer, hydrostatic shock, or the temporary cavity methodology of flawed work such as RII. (1)

The truth is, the whole idea of handgun knockdown power is a myth. It simply doesn’t work that way. The FBI report further clarifies:
A bullet simply cannot knock a man down. If it had the energy to do so, then equal energy would be applied against the shooter and he too would be knocked down. This is simple physics, and has been known for hundreds of years. The amount of energy deposited in the body by a bullet is approximately equivalent to being hit with a baseball. Tissue damage is the only physical link to incapacitation within the desired time frame, i.e., instantaneously. (2)

The report cites previous studies that have calculated bullet velocities and impact power, concluding that the “stopping power” of a 9mm bullet at muzzle velocity is equal to a one-pound weight being dropped from the height of six feet. A .45 ACP (45 auto) bullet impact would equal that same object dropped from 11.4 feet. That is a far cry from what Hollywood would have us believe, and actually flies in the face of what even many in law enforcement have come to mistakenly believe.

The FBI report also emphasizes that unless the bullet destroys or damages the central nervous system (i.e., brain or upper spinal cord), incapacitation of the subject can take a long time, seemingly longer if one is engaged in a firefight.

Failing a hit to the central nervous system, massive bleeding from holes in the heart or major blood vessels of the torso, causing circulatory collapse is the only other way to force incapacitation upon an adversary, and this takes time. For example, there is sufficient oxygen within the brain to support full, voluntary action for 10-15 seconds after the heart has been destroyed. (3)
More often than not, an officer firing at a suspect will not immediately know if he or she has even struck the target. The physics are such that the body will rarely involuntarily move or jerk, and usually there is no noticeable spewing of blood or surface tearing of tissue. Often there is no blood whatsoever. (4) That is why military surgeons and emergency room physicians take great time and pains to carefully examine gunshot victims for any additional small holes. Often that is the only indication the person has been shot.

Personal Experience

But let’s be real here. I can cite numerous additional academic and scientific sources that support this article, but I know how cops think. We’re not always the most trustful of academics, especially when it comes to our street survival. So let me add my own personal experience to the data. Please allow me to go beyond the cold facts and share with you why I know what I’m telling you is the truth.

In the mid-1980s I was involved in my first shooting as a police officer. But to give the story context, I must go back to 1982 when I graduated from the Long Beach Police Academy. The first thing I was told by experienced training officers I trusted and looked up to, was to “get rid of that pea-shooter 38 they issued you and buy a real gun with some knockdown power!” Although we were issued .38 caliber revolvers, we were authorized to carry a number of different caliber weapons on duty, the largest of which was the 45 Long Colt.

The .45 Long Colt round next to the diminutive 9 millimeter.

Imagine my surprise when I was confronted by a suspect armed with a shotgun in a dark alley and my Long Colt didn’t live up to its billing. I fired five rounds at the suspect. It wasn’t until I fired my last shot — intentionally aimed at his head — that he went down. I can’t begin to relate to you the surprise and horror I felt when there was absolutely no outward indication I was hitting my target. It was the kind of situation cops have nightmares about.
What actually happened? I fired five rounds at a distance of about twelve feet. The first one missed completely. The second struck his upper leg and broke his femur. The third struck him in the shoulder/chest. The fourth round hit him dead center—in the heart. And of course, the fifth was a headshot. Three of the five rounds created fatal wounds, though only one had immediate results.

Needless to say, I was pretty shaken by the whole thing. Not by the morality of what I’d done; the suspect had already fired at a bystander and taken a hostage earlier. He was also high on PCP. That wasn’t my inner struggle. What shook me was how unprepared I felt; how totally off guard I was taken by what occurred. No one ever told me it would be like that. The reality was contrary to everything I thought I knew about deadly force.
That experience more than any research or study is the reason is why I am writing this article. Police officers risk getting into shootings every day; we need to know the dynamics of how a shooting incident may unfold. It will affect our equipment, tactics, and most important, our mindset. We need to know that rarely will one shot incapacitate an assailant. We further need to be able to explain this when our fellow officers are involved in shootings where multiple shots are fired. The public honestly believes it’s like the movies. Why would we ever need to fire twenty or thirty rounds to subdue an armed suspect? Problem is we can’t teach it or explain it until we understand it ourselves. (5)

Footnotes:
1. Patrick, Urey W., Federal Bureau of Investigation, Firearms Training Unit, “Handgun Wounding Factors and Effectiveness,” p.13. (1989).
2. Ibid., p.9.
3. Ibid., p. 8.
4. Newgard, Ken, MD, “The Physiological Effects of Handgun Bullets: The Mechanisms of Wounding and Incapacitation” (1992).
5. For you visual learners still unconvinced, I highly recommend viewing the Discovery Channel MythBusters segment, “Blown Away,” (Brown Note Episode, Second Season), where the knockdown power myth is visually and scientifically debunked once and for all.
Interesting stuff Josh
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Old 06-09-2010, 08:18 PM   #3
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Yes indeed this Tall Tale seems to have been around longer than even the age of electronics started .

I remember when in my 20's I ran into an old friend from high school at a bar and while catching up and drinking talking guns and it turns he had dissapeared into the Army for 4 years which came with many interesting stories the best of which was what his DI had told him regarding the 45 while in Basic training .

I couldn't help but almost falling off of my Bar Stool when he said that this clown had told the class as they were about to get to shoot the 1911 and that being hit with a bullet from it was like getting hit with a Brick traveling at 90 MPH !!

When I finally caught my breath and could talk I had to tell him that between a Brick going that fast and a little 45 bullet the brick would win hands down in the stopping power department but the 45 had much better Killing power .

I then had to sit and try to make him understand the difference betweeen the two .

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Old 06-09-2010, 08:29 PM   #4
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This issue has been beat to death in many threads.

I always come back to the training I received at the hands of Rob Pincus. Combat Focus. Your attention is fixed on one threat, you fire your weapon until that threat is eliminated, then you move on to the next threat.

Now, when you are slinging .45ACP rounds as fast as you can pull the trigger, those threats do go away faster than if you were shooting the same number of bullets from say a .22LR

That doesn't mean the .22LR can not be effective in the same situation, it will just take more shots to complete the process.

Either way, with Combat Focus, you stay trained on that one target until the threat is eliminated. If it takes 1 shot, great, but if not, you are trained to continue shooting until you have achieved that conclusion.

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Old 06-09-2010, 08:48 PM   #5
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Drop the one with the shotgun first.

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Old 06-10-2010, 03:01 PM   #6
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So the moral of the story is... go for the head-shot?

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Old 06-10-2010, 03:20 PM   #7
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So the moral of the story is... go for the head-shot?
I hope your kidding.

I would say the moral is don't get stingy with your bullets in a self-defense shooting situation.
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Old 06-10-2010, 03:38 PM   #8
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Look, everyone knows that if you get hit with a .45 you'll immediately be picked up and thrown 32 feet through the air. If it's a center mass shot, the 32 foot flight will include a few back flips as well. One caveat is that the .45 round must come from a quality 1911.

This must be true as I saw it on TV...

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Old 06-10-2010, 04:09 PM   #9
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I hope your kidding.
That's what the question mark is for. Doesn't make sense to me either.
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Old 06-10-2010, 07:27 PM   #10
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It makes perfect sense.Hit the guy with what you got where it hurts as much as you need to till he drops.Dont rely on 'one shot stops' or the 'massive knockdown power' of caliber X,or the 'super hydrostatic shock' of a $2 dollar handgun bullet.(Dillinger I'd be pretty stingy with a magazine or a cylinder full of $2 bullets,wouldn't you?)

Dont choose your weapon or your ammo believing it will do the job for you.Choose it because it gives you that 'special' feeling deep down inside.

Choose it for your ability to use it well and your comfort with the weapon.

That being said-there is no point to the 'caliber wars'.
Were better off discussing how to train to hit the vitals.

While all are not 'equal',if you make a good decision and choose a gun/ammo combo that works well for you and gets the job done,and you learn to use that weapon well-it doesnt matter if you like a .45 or a 9x19.

Both of them have plenty of ballistic energy and will do the job of putting down a man sized target by hitting his vitals.

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Last edited by KalashnikovJosh; 06-10-2010 at 07:34 PM.
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