What is "Knock Down Power"

thesheepdog said:
Peetzakilla,

The math is there, but think realisticly here; you have to factor deceleration as well; because once a bullet expands, you're creating surface area, and surface area will create drag.
How does this apply if your bone gets shot? Think of shooting a 2X4 with a hollow point. I am sure you have done this, and i am sure you can disagree that it's moving at 1MPH-given a 2X4 isn't 150lbs.
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There's nothing more realistic than the actual physical laws that govern the scenario.

There are two different things.

One is the damage done by the bullet. Yes, if it shatters bone, crushes your spine, splatters your brain, it's going to "knock you down".

The OP is not asking if a bullet can cause damage. He's asking if the actual ENERGY of the bullet is enough to knock you down. The answer to that question is, unquestionably, demonstrably, inarguably No. Search uTube. There are videos there of a guy taking an ?Ak-47? into a trauma vest at POINT-BLANK range, while standing on ONE FOOT. He barely wobbles.


You speak of deceleration. Fact is, deceleration reduces the effect. The most possible effect that the bullet could have on the target is if it stops, essentially, "instantly". An "instant" stop transfers all of the energy in the shortest amount of time. Shorter time equals greater force (f=a/t) A bullet that slows down over a distance imparts LESS force on target.

The 1.5 mph in the math above indicates that the bullet stops (essentially) INSTANTLY on impact.
 
Consider that the "push" felt by the recipient is going to be about the same as the recoil felt by the shooter, equal and opposite & c.
 
Knock down power is a sure thing when you step in front of a car going 50 mph.

It's a fair possiblity when you step in front of a 30-06 slug at 2700 fps or a 12 gauge.

But in handguns it's an iffy thing. A real iffy thing!

Deaf
 
Slight correction....

In terms of "momentum", the time that it takes to apply the momentum makes no difference in mathematical terms. The transfer of momentum would result in a theoretical speed of 1.5 mph for the 150 pound person whether it took 1 second or one microsecond to transfer. However, what does make a difference is the amount of time that a person would have to REACT to the applied momentum. Time to compensate reduces the effect. Regardless, in this case, we're talking about a near instantaneous transfer of momentum. That transfer would, without doubt, "jolt" a person. It would not however, "knock them down" or "blow them off of their feet".


I can't find the video right now, but it's out there. It's two guys, one wearing a vest. He stands on one foot and the other guy shoots him point-blank with what I remember being an "Ak-47" type rifle. He doesn't even lose his balance.
 
The entire discussion of "knockdown power" is a red herring and a waste of time.

I've posted this before, I'll post it again.

Thoughts on stopping an attacker

THE OBJECTIVE: Stop the Bad-guy from doing his bad-thing.

There are two aspects to being shot.

1) The Psychological aspect where someone might go "oh Snap, I've been shot" and collapse in panic and terror, or at least run away.

2) The physical aspect of being shot where unavoidable physical response to trauma determines what happens next regardless of attitude or willpower.

The majority of the time a human who gets shot thinks (Psychological) "oh, I've been injured, I don't want that to happen again" and ceases most/all aggressive actions. This is a desired outcome, minimal force and quick capitulation....BUT...those who don't do that (for whatever reason, drugs, psycho, high pain tolerance, adrenalin, distraction, etc.) will ONLY, let me stress that again, ONLY be reliably stopped under all conditions by severe physical trauma in one (or more) of three areas.

1) Central nervous system disruption (brain, spine)...the electrical signals that control the body can no longer be sent.

2) Support structure (skeleton) disjunction...if you break the supporting structure (bones) the muscles have no levers to move the body about.

3) Exsanguination (bleeding out)...If the blood pressure drops below a certain point there is no longer an oxygen supply to the brain and the central nervous system shuts down (going back to #1)

1 and 2 can take place instantly with a good shot, #3 can take ANY amount of time from about 12 seconds (how many times could someone stab you in 12 seconds?) to several hours.
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So if you are looking for "stopping power" in a handgun the three items above (and the ability to hit a target accurately) are more critical than any discussion of some phantasm like "knockdown power".
 
thesheepdog said:
I bet you that a bullet would knock a human off their feet easier than one of my Krav punches to the face/chest.
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I'll take that bet. You set up the time in which you're ready to make the trip here to demonstrate your technique and I'll set up the location. For my argument of the case a bullet wouldn't physically knock a human off of their feet as easily I present to you ANY WWII, Korean War, Vietnam, or Middle East vet that has been in actual combat for their MOS. See if ANY of them will attest that A bullet fired out of their M16s, M4s, etc. and impacting the enemy from a normal, balanced stance.

We can provide formulas generated from a physicist but what's the point? If there was merely a shred of actual common sense applied here, one would know a bullet less than the diameter of 1/2inch travelling into or through the human body isn't likely going to decleat him John Madden style.
 
If the shooter remained on their feet the target is not going to be knocked over.

Energy is the ability to do work, like break bones, disrupt tissue, and penetrate.

More energy improves you chances of doing more damage, more penetration being the chief thing here.. The more tissue you can go through, the more likely you are to damage something important.
Temporary wound cavities that exceed tissue stretch limits also contribute.


Momentum is what would 'knock down' a target, and nothing you can fire has enough momentum 9or you would be on your ass also).
 
Not clear on the definition the OP is using for "knockdown" power.(?)

I think it's quite clear and conclusive that a bullet will "neutralize" and/or "immediately incapacitate" a person if the subject suffers penetration to the CNS, regardless of caliber.
 
While the conversation is about handgun ammo I feel real hunting experences should count. I was a big game guide for 9 years and have personally shot well over 100 head of big game and have seen over 200 head taken. From what I have seen there is no majic knock down power unless vast overpower cartridges are used on very small animals. I saw a 1 pound cottontail rabbit shot in the head with a 7mm Rem mag and still stay on his feet and need a finishing shot. Unless the spinal cord is impacted the chances of an instant knock down is slim but not impossible. Head shot which I despise arent even instant knock downs. I witness a small 2 point mule deer shot in the head at close range with a 300 Weatherby Magnum that dang near escaped and didnt actually show signs of being hit except for beating a fast retreat. I have shot a 32 pound javalina with a 45 ACP. The animal showed NO signs of being hit and just ran off. It showed up a few seconds later and took a second hit that he ran away from to finally bleed out. I shot a @100 pound antelope with the same 45ACP using Winchester Silvertips bullets. I hit him 9 times before he finsally laid down. The finishing shot was in the neck at point blank range. He didnt even blink. I shot a wounded yearling deer that I used a 12 guage slug to finish him off. Range was point blank, shot between the eyes, he also just blinked and started shaking his head. I had missed the brain by an inch and needed a second hit. So if a 12 guage slug at point blank range on a 75 pound animal doesnt knock down instantly I doubt any handgun would reliably be counted on to do the same.
 
Knock Down Power?

No such thing. Stopping power? Yes. Hard to messure, however.

Hit center mass with any caliber and fire untill threat is stopped.

Not the sexy, majic bullet solution many are looking for, I know.

Peachy
 
Well, I don't know if I would be knocked off my feet after being hit by a powerful handgun round, but it would definetely create a massive amount of ouchies. :rolleyes:
 
I can't find the video right now, but it's out there. It's two guys, one wearing a vest. He stands on one foot and the other guy shoots him point-blank with what I remember being an "Ak-47" type rifle. He doesn't even lose his balance.
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It was an FAL rifle in .308 which puts out considerably more energy/momentum than the AK47 round. The results were as you state.

http://www.thefirearmblog.com/blog/2008/06/03/shot-at-point-blank-with-308-and-44-magnum/

Cirillo relates a gunfight in which a criminal was shot in the chest at close range with a 12ga slug and didn't flinch. The policeman shot the other criminal thinking he had missed the first man. After dropping the second he came back and shot the first man again who dropped at the second shot to the chest. Both slugs were good hits in the chest.

There have been instances of people taking 12ga slugs to a bullet proof vest and showing no evidence of being hit.

The Mythbusters busted this one wide open by shooting a human weighted crash dummy at point blank range with a .50BMG rifle after placing a piece of armor plate in his chest to make sure the round would stop. The dummy was dislodged from the supports but fell more or less straight down. There was no pronounced backward movement.

By the way, the supports were designed such that a thrown baseball would easily knock the dummy off the supports. Even so only the 12ga and the .50BMG were able to dislodge it from the supports. Even shooting it with a long burst from Thompson .45ACP machinegun didn't knock it off the supports.
 
JohnKSa said:
It was an FAL rifle in .308 which puts out considerably more energy/momentum than the AK47 round. The results were as you state.
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That's the one, thanks John.

I'm like the antis.... I knew it was one of those evil looking, military rifles that no civilian should ever own.:D;)
 
"Dropped in his tracks."

A recent stint in the hospital gave me time to watch some TV. I found the "Pursuit" channel and began watching the bullet-hunters on there. They seldom credit gun, bullet, scope, powder-load, etc. so I'll have to guess. Of course the film is edited. I'm guessing .22-250, .223 (because the gun was an EBR), with .243, ..30-xx, and .308 stated against deer. Every time, one-shot, one-drop. No running off, just a few upside-down ballet steps and Bambi's dad is finished. I see that the shot is shoulder-heart area, which is perfect placement, and the carcass might lay at 60 lbs coyote, up to 200 lbs. max. buck white-tail. What bullet-weight-to-critter-weight is affecting these perfect kills? What is the man-equivalent?
 
It's not a bullet weight to body weight ratio, it's more complicated than that.

When you get into massive trauma to an unsuspecting animal the results are often more spectacular than one might expect. Rifle bullets can really tear up a lot of tissue compared to handgun bullets. Unlike pistol bullets that create temporary cavities that typically rebound leaving only bruising, high powered rifle bullets can create large impact cavities that literally tear tissue apart and severely traumatize adjacent nerves and organs.

The animal still isn't "knocked down" but it may go down instantly at the shot due to the shutdown of major organs and other trauma.

Here's some interesting reading.

http://ethesis.helsinki.fi/julkaisut/laa/kliin/vk/jussila/
 
What Causes This?


If someone is sitting in a chair and you stick them in the rear with a very low velocity and low weight pin they will jump up. I can find no term for this.
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It's called fight or flight response. It's basically just an adrenaline rush to pain, stress or any intense nervous response.
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No, it is not flight or fight response and it is not caused by an adrenaline rush to pain, stress, or intense nervous system response. The reaction happens long before the andrenaline has a chance to get into the the blood stream to do its work. It is a startle reflex. Being poked with a straight pin you know is going to happen and cause you pain does not result in the same reaction as being poked by surprise by a straight pin. The same amount of pain may occur either time, but in the former situation, there is no startle reflex response and no following adrenaline dump (assuming you aren't deathly afraid of pins or needles). In the latter, it is a startle reflex that may or may not be following by an adrenaline dump.

A startle reflex/response - a complicated involuntary reaction to a sudden unexpected stimulus (especially a loud noise); involves flexion of most skeletal muscles and a variety of visceral reactions.
 
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If you've ever been knocked down by anything, you should believe that there is such a thing as knockdown power. It happens all the time. Think about boxers, for instance. What you have to do is ignore all the reasons why and accept that it is possible to knock someone down, although it doesn't follow that you can count on it. Think about the boxers, again.

There might be some mystery to it but I'm not interested in that part. Hits to certain parts of the body will definately put a person or an animal down. Don't ask me about what parts but a hit to the head often will. But it isn't that simple.

Just because you've knocked someone or something down, they won't necessarily stay down. They can easily (easily might not be the right word) get back up and run away or for that matter, attack. But all the same, they were knocked down and it wasn't magic but it probably isn't like the way it's shown in the movies, either.
 
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