Knockdown Power?

[tipoc]

Since it clearly doesn't exist, maybe we shouldn't call it anything at all. Just a thought...

Seriously, although most serious shooters probably know that anything that one person can carry and shoot that doesn't send an explosive charge downrange won't knock a person down, the movies work so hard to perpetuate the myth that many people do believe it. When we use the term (knowing it's not accurate) we also help perpetuate the myth which is the opposite of what we, as experienced and responsible shooters should be doing.

Also, based on what I read on the forums, even some shooters who should know better still seem to believe that the force of a bullet impact can knock someone down. And other shooters think that while some bullets and calibers have the ability to knock someone down, others simply can't--that there's a practical difference in "knockdown power".

I see it all as part of an unhelpful mentality that places more emphasis on bullets and calibers and guns and deflects away from the truly important aspects of handgun self-defense. I posted my own personal definition of Caliber War on THR awhile back--one part of it says that a Caliber War is a discussion in which people who really know the truth about what wins gunfights pretend instead that you can buy it in boxes of 50 from the gun store--and argue about what markings should be on the box.

It struck me that perhaps I was being overly optimistic about what people know or don't know about what wins gunfights and I figured that clarifying the misconceptions about "knockdown power" might be a good place to start.

"Knock down power" or "Stopping Power" were terms that were commonly used by shooters like Elmer Keith, Jeff Cooper, Gen. Julian Hatcher and many others who knew well that bullets did not automatically knock people down or stop them. Yet they still used the terms.

It was General Hatcher who was the first to develop the mathematical formulas to illustrate that a rifle bullet would not knock a man down. He was the first to develop a simple test of this by having a soldier stand and hold a steel plate of known weight and size and have someone shoot a rifle round at the plate. This was back in the 1920s and 30s. He wrote about this. You can see it in "Hatcher's Notebooks". Yet he still used the term stopping power and knock down power.

The terms were used to indicate that one round delivered a heavier blow than another. That the .357 Magnum delivered a heavier blow than the 38 Spl. Or that the 30-06 had more knock down power than the 7.5x55 Swiss, the 45-70 more stopping power than the 44-40 from a carbine.

Or that the 40 S&W has more stopping power than the 32 acp. It means that one round has the potential to deliver a more devastating wound than the other. It brings no guarantees of course.

The folks who leap up and down whenever they hear the mistaken impression that a 45 acp will automatically knock a man's arm off are usually arguing against straw men or folks that are repeating old husbands tales. They enjoy over acting it appears.

tipoc

 

[JohnKSa]

"Knock down power" or "Stopping Power" were terms that were commonly used by shooters like Elmer Keith, Jeff Cooper, Gen. Julian Hatcher and many others who knew well that bullets did not automatically knock people down or stop them. Yet they still used the terms.

Many years later, we're still using the same terms to confuse people--intentionally or otherwise. And make no mistake, people ARE being confused--not just the uninitiates either. You don't need to read the gun forums long to realize that even many gun enthusiasts believe that the term "knockdown power" means exactly what it seems to mean.

 

[doubleh]

The point was how little the impact made the dummy move. However, if you want to see results from a dummy shot that could be knocked over, I posted that earlier in the thread in post #14 on the first page. Same stuff pretty much. The dummy was dislodged from its supports and then fell more or less straight down. Almost no backwards movement at all.

The title of the thread was "Knock down power", not "How little the impact makes the dummy move". Upon seeing the setup it's quite obvious that the dummy is going to stay upright and not be knocked down. Even if there was such a thing as knockdown power this rig wasn't going to demonstrate it.

 

[rsrocket1]

I've been watching airgun videos of our friends across the pond taking out rats and squirrels with pellet guns limited to 12 ft-lbs of energy scoring brain shots to the rodents and it looks like they simply go to sleep. Then I get auto fed some guy prairie dog hunting with a 22-250 at 3500 fps and the rodent getting peeled open, pulled out of the hole and thrown 12 feet away with a shot "somewhere near the furry part".

That's real knockdown power

 

[huntsman]

^Velocity and size matters

Knock down is a bit vague, stopping not as much(as long as it means cease previous actions).

Folks is going to believe in what they believe and influences vary.

I’m comfortable with my belief that life doesn’t offer as many absolutes as we like to believe, whether it be magic bullets or ballistics that some cling to.

 

[Dibbs]

I guess we've now established that knockdown power works better on prairie dogs?

 

[murf]

an entertaining thread. makes me want to watch "quigley down under" all day.

murf

 

[ATLDave]

As others have no doubt said, few gun people today think or use "knockdown power" to suggest that momentum transfer will physically carry a man off his feet. Obviously, if the shooter isn't pushed down by the recoil, the person on the other end is not likely to be, either.

I think almost all current usage among gun people is simply shorthand for "the propensity to bring an instant or near-instant cessation of voluntary activity by the target and/or propensity to incapacitate the target." Neither a .22lr nor a .308 Winchester round have enough momentum to physically carry a man off his feet, but one of them has a much greater propensity to rapidly incapacitate the person (or animal) shot.

 

[1911 guy]

Stopping Power is done with a cement truck at 70 MPH.
Handguns are anemic, even when compared to the mildest rifles. But I do enjoy seeing stuff shot up on video.

 

[George Dickel]

As I read it, this thread was about the 50 BMG and that was what was shown in the video. If a person is hit center mass with a 50 BMG he will not be getting back up again in this life. A 750 grain bullet at 2400 fps will make a hole right through a man with a rather large exit hole. I've spoke at length with a friend of mine who in his own words said "I spent almost my entire adult life in the middle east". He has seen the after effects of hits by a 50 BMG and has said that it will kill you dead with a center mass hit. He has seen arms and legs blown off by that round but also said that the body doesn't go flying back when hit. He had to shoot a man in the chest with a 12 gage using 00 at about a foot, it made a 3 inch hole in the chest from front to back. He could see the wall behind the guy through the hole. The guy dropped straight down unlike how Hollywood shows it in movies with the body being blown back 20 feet. I've never equated "knock down" with being thrown backwards any distance, my understanding of the words is you will be dropped to the ground.

 

[JohnKSa]

The title of the thread was "Knock down power", not "How little the impact makes the dummy move". Upon seeing the setup it's quite obvious that the dummy is going to stay upright and not be knocked down. Even if there was such a thing as knockdown power this rig wasn't going to demonstrate it.

If you find it difficult to draw conclusions about momentum transfer from viewing the momentum transfer in the video, then, in post #14 of this thread, I posted information about another test which does NOT involve a dummy being hung and swinging. It answers all your concerns.

That's real knockdown power.

It is certainly true that if you shoot something very small and light with a powerful rifle, it will move the target around impressively. Even with an airgun, if you get a small enough target you can make it move impressively. People, however don't come in sizes that small or weights that light. Even powerful rifles won't move a person around impressively with the impact force from a bullet impact.

As I read it, this thread was about the 50 BMG and that was what was shown in the video.

The thread is about bullet impact force. The video shows a bullet impact force that is 9 to 10 times more powerful than any handgun round and yet the bullet impact force barely moves the target.

...but also said that the body doesn't go flying back when hit. He had to shoot a man in the chest with a 12 gage using 00 at about a foot, it made a 3 inch hole in the chest from front to back. He could see the wall behind the guy through the hole. The guy dropped straight down unlike how Hollywood shows it in movies with the body being blown back 20 feet.

Yes, that's what the thread is about. People don't get thrown around or "knocked down" by bullet impact force. Not even when the bullet is from a .50BMG rifle.

Clearly bullets can kill or injure or incapacitate, but they don't do it by knocking people down. They do it by poking holes through important parts of the human body.

 

[Drail]

It really is a shame that public schools don't teach classes in Physics today. We had them in the 8th and 9th grades in the 60s and they were the most interesting and useful classes I ever attended. Industrial Arts were a close second. Students today graduate high school without the slightest idea how anything works except for computer programs.

 

[Double Naught Spy]

I think you are all misinterpretating the intended meaning of knockdown power. If you hit someone center mass with that bullet, you will put them down. You will injure them so badly they can’t stand most likely ever again. That is a knockdown to me. Who cares if the bullet force doesn’t knock an inanimate object down?

I think there is a distinct difference between being knocked down and being put down in this thread and with the intent of educating folks that bullets don't actually knock down people despite the use of the phrase.

Multiple anecdotes do not constitute data.

Actually, multiple anecdotes are data, if the information contained is accurate and used for analysis. Any single point of data may be anecdotal in and of itself, but it is still a datum. Anecdotes may not be a representative sample about the phenomena to which they may be referenced, but they are certainly a sample of data. However, along the lines of what you are saying, multiple anecdotes do not necessary substantiate a conclusion drawn from them as they may constitute an insufficient sample.
.

 

[rpenmanparker]

I think there is a distinct difference between being knocked down and being put down in this thread and with the intent of educating folks that bullets don't actually knock down people despite the use of the phrase.



Actually, multiple anecdotes are data, if the information contained is accurate and used for analysis. Any single point of data may be anecdotal in and of itself, but it is still a datum. Anecdotes may not be a representative sample about the phenomena to which they may be referenced, but they are certainly a sample of data. However, along the lines of what you are saying, multiple anecdotes do not necessary substantiate a conclusion drawn from them as they may constitute an insufficient sample.
.

Insufficient sample is just the beginning of the problem. Lack of experimental control is equally important. Not to mention the question of the validity of the “data”. Is an anecdote really what it purports to be?

 

[Double Naught Spy]

Insufficient sample is just the beginning of the problem. Lack of experimental control is equally important. Not to mention the question of the validity of the “data”. Is an anecdote really what it purports to be?

Are the data you say anecdotes aren't really what they are purported to be? How would you know without evaluating them? We can play this game all day long with casting aspersions.

Apparently I was being too subtle. Trite dismissal of anecdotal information is a fallacy in and of itself without actually evaluating it just as it would be for any data. Just because you deem it "anecdotal" does in no way detract from or bolster its authenticity. Anecdotal information is a type of data. You may not like it, but it is still data.

 

[ATLDave]

Most problems/decisions that humans face are not susceptible of a perfectly controlled laboratory-grade experiment. It's great when we can get that, but most decisions that humans make have to be informed by such things as:

• Observed or relayed experience (i.e., anecdotes)
• Reasoning from first principles
• Extrapolation from laboratory/controlled experiments of perhaps-semi-analogous phenomena
• Aggregated experiential data, replete with confounding variables
• Expert analysis
• Convention/herd-following (assumption of rational decision-making being rewarded over time)

That's the kind of stuff we rely on every single day to make decisions that are, for most of us, a lot more important than what caliber to carry (and, in 99.9+% of cases, never put to the ultimate test).

 

[rpenmanparker]

Well I guess I got told! It will be a long time before I make the mistake of repeating an old joke like that again. Sheesh.

 

[doubleh]

Well I guess I got told! It will be a long time before I make the mistake of repeating an old joke like that again. Sheesh.

As did I. All I did was point out that the setup in the original video wasn't capable of showing "knockdown" power or the lack of it. I won't make that mistake again either. I'm not in the least "concerned" about it one way or the other.

 

[cheygriz]

I'll betcha we could determine, with a 75 percent level of confidence, whether a person is a "believer" in KD power, or a "non-believer" by finding out who his gun magazine heroes are!

 

[JohnKSa]

All I did was point out that the setup in the original video wasn't capable of showing "knockdown" power or the lack of it.

"Knockdown" power is momentum transfer--the idea that an object must be actually knocked down before momentum transfer is observable may seem intuitive, but it isn't correct. Any experiment that demonstrates momentum transfer (shows an object moving as the result of a moving object hitting it) is a demonstration of "knockdown" power.

The original video shows momentum transfer is occurring (as physics says it must) but also demonstrates just how little that momentum transfer actually moves the dummy.

Given that the momentum transfer in the original video is roughly an order of magnitude more than is possible with typical self-defense centerfire handgun rounds and that the dummy is lighter than a human, it is easy to see that there isn't going to be anywhere near enough momentum transfer from even a powerful rifle round to actually knock a person down.

 

[ATLDave]

But people can be induced to fall down by things that do not have the momentum to physically shove them off their feet. A person might be hit in the head at an inopportune angle by a punch or other moving object, which might impart enough rotational speed to the skull to induce a concussion... yet that same punch or moving object, if it struck them squarely in the chest would not. Similarly, people who have been punched in the gut have been known to double over and then even fall down, despite the punch not having enough momentum to cause them to physically fly backwards. Did these collisions exhibit "knockdown power"? Well, it all depends on what you mean by that phrase.

 

[fastbolt]

The term "stopping power" belongs in conversations about disc brakes.

The term "knockdown power" belongs in conversations about boxers or UFC matches.

 

[ATLDave]

fas', what phrase or word do you like to use to encapsulate the concept "the propensity to induce an immediate or near-immediate incapacitation sufficient to preclude (for whatever duration) further volitional offensive acts or movement"?

 

[JohnKSa]

fas', what phrase or word do you like to use to encapsulate the concept "the propensity to induce an immediate or near-immediate incapacitation sufficient to preclude (for whatever duration) further volitional offensive acts or movement"?

Incapacitation, in addition to being a very different thing from being knocked down, is also a FAR more general category than being knocked down.

It's quite easy to see, for example, that a person can certainly be knocked down without being incapacitated in the least. It's also not hard to see that a person could be incapacitated without ever having been knocked down.

But people can be induced to fall down by things that do not have the momentum to physically shove them off their feet.

Sure.

One could tie someone's shoelaces together and make them fall down.
Or one could catch a person at just the right moment and startle them with a light touch and cause them to fall down.
One could pull someone's chair out from under them as they were sitting down.
One could shoot a person with a dart laden with a paralytic.
Or one could compromise a person's CNS by inserting an icepic in a strategic location.

The end result of all of those things is a person on the ground but none of them could accurately be described as knocking someone down.

Did these collisions exhibit "knockdown power"? Well, it all depends on what you mean by that phrase.

There are many, many, ways to get a person on the ground without actually using momentum transfer/bullet impact force to take them off their feet in the absence of any other circumstance that predisposes them to fall.

A bullet can put a person on the ground in many ways. It could kill them outright. It could damage some structure (joint/bone) or mechanism (muscle/nerve) necessary to maintain a standing position. It could scare them and cause them to decide to fall down/sit down/lie down. It could cause loss of blood pressure leading to unconsciousness. It can cause sufficient pain to make a person fall to the ground either voluntarily or involuntarily.

But a bullet can't knock a person down. It doesn't have the impact force/momentum transfer to take them off their feet in the absence of any other circumstance that would be expected to cause a person to fall down.

Ok, let's step back and think about the context for a moment.

Knockdown power is, and has been, most commonly described comparatively. That is: "This bullet has MORE 'knockdown power' than that other bullet." Or: "That caliber has LESS 'knockdown power' than this caliber."

Obviously then, it doesn't make sense to define "knockdown power" in terms of things that all bullets in the category do pretty much the same. After all, any bullet will make a person fall down if it cuts their spinal cord or ruins a joint required to stand up, or hurts/scares them enough to make them give up. In addition, it's quite common to see very simple examples of momentum transfer cited as evidence of "knockdown power". e.g. Bowling pin movement, steel target movement, etc.

I don't really think there's a lot of genuine confusion about what people think knockdown power IS. I do see a lot of confusion about what people think about how much knockdown power bullets have (essentially none) and what that knockdown power can DO.

 

[ATLDave]

I think you're really giving that straw man hell!

No, that's not fair. No doubt there are a few novices in gun-world who believe that people can be blown backwards through plate-glass windows. But not many, and nobody here (unless I skipped a post - certainly a possibility). Various people, including me, keep pointing out that there is generally a lack of confusion on this myth that you are furiously debunking... but that most gun people who are using that phrase are perfectly aware of the physics involved, and do not mean it in the way you (accurately) have argued cannot be true.

If you want to pound on the scarecrow some more, don't let me get in the way of your fun. You've definitely got the upper hand.