Knockdown Power?

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Whatever ammo/reloads are the most explosive and tears up the most stuff on my home range are the bullets/calibers/loads that impress me and I try to duplicate. Whether they have more or less knock down power I do not know. And hope I never have the opportunity to find out.
 
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?
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If we're talking about the .50BMG, that's probably true. If we're talking about handguns it's usually not. There are many instances of people being hit in the chest with handgun rounds and not just surviving but also continuing to function. Last statistics I saw indicate that something like 80% of people shot with handguns survive.

Of course, it is true that when someone is shot, the most common response is for them to CHOOSE to stop what they're doing and start trying to think about getting prompt medical attention. But that's not really about the bullet, or incapacitation, or the severity of injury, nearly as much as it is about their personal mindset and motivations.
Now imagine your walking along nice and relaxed, peaceful like, totally lost in your own thoughts and not on your guard. Along comes someone that sneaks up behind you and hits you in the shoulder or ribs with roughly the same momentum change as the recoil of your favorite center-fire rifle or shotgun you might use for deer or elk hunting, completely and totally unexpected. I suspect most people would be knocked down.
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I think that there would very likely be some sort of "startle response" but I doubt many people would actually go down. The man in the video who was shot with the .308 stated that the force of impact was less than that of a punch.
Couple that with raw tissue damage (especially structural damage to bone) and possible partial nerve damage in the impacted area or even CNS damage and you get real world knock-down power.
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You get killing and incapacitation power from those things, but not "knockdown" power. In other words, the bullet may kill, or it may make it impossible to stand by destroying a joint or bone or nerve necessary for standing, but the target won't be "knocked down" by the force of impact.

So am I picking nits? Well, perhaps, but not without point entirely. The term "knockdown" has a general meaning that everyone believes they understand. Therefore, if we use it to mean something other than what everyone already believes it means, we're misleading them, albeit unintentionally. And, while a number of people on this thread have mentioned that when they use the term, they understand it's not really about bullet impact force knocking someone down, I think that even on this thread we've gotten responses pushing back and indicating that they really do believe that bullet impact force can knock a 180lb target down.

Either way, the terminology is problematic. If we're going to use "knockdown" to mean something other than "knockdown" then we should come up with a more accurate and less misleading way to get the point across. And those who actually think it is literally accurate need to understand the truth.
 
RecoilRob said:
I have a bone to pick with shooting the BMG in a 20" barrel.:( Velocity with 750 A-max is probably struggling to hit 2200 fps so this is really throttling the cartridge down to almost black powder levels. It's like putting a two barrel carb on a 454....yes, you ARE driving a Big Block but it's so choked that it's not putting out what the name implies.
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Well, I guess you are referring to the 7.5L GM large block. It's not carburetion, anymore, it's one of
a series of injector systems, but we get the point.

GO, Gators!
 
Trunk Monkey said:
So, let's take a look at what you claimed



You even clarified that they will be so badly injured that they will most likely never stand up again.



Again, most people shot with handgun bullets do, in fact, stand up again. They do survive and they do go on to live long lives after being shot.

There's a reason that most people train to shoot multiple times. There's a reason that most reputable trainers teach their students to continue to engage until the assailant is no longer a threat.

The fact is that a large portion of the time getting shot doesn't initially change the behavior of the person being shot. People continue to attack with bullet holes in them every day.
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We are both claiming facts not in evidence. Who’s right? It isn’t obvious from the information provided. I can live with that. But I will ask again. If gunshots don’t reliably stop assailants, why do all sorts of folks carry guns for protection? What’s that they say about the definition of crazy, doing the same thing over and over and expecting a different result?
 
Here are the Shooting stats for Chicago in October this year

I think this is a pretty good survey of the real world
Overall, 2419 shooting produced 466 deaths
That is about a 20% rate of fatality.

Shot & Killed: 23
Shot & Wounded: 75
Total Shot: 98
Total Homicides: 26

Year to date

Shot & Killed: 401
Shot & Wounded: 2018
Total Shot: 2419
Total Homicides: 466
 
JONWILL said:
Here are the Shooting stats for Chicago in October this year

I think this is a pretty good survey of the real world
Overall, 2419 shooting produced 466 deaths
That is about a 20% rate of fatality.

Shot & Killed: 23
Shot & Wounded: 75
Total Shot: 98
Total Homicides: 26

Year to date

Shot & Killed: 401
Shot & Wounded: 2018
Total Shot: 2419
Total Homicides: 466
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Thanks for that. But the required information is how many of the single hits were center mass, and how many of those caused the shot person to fall down to the ground by any mechanism. That is the area of dispute.
 
If gunshots don’t reliably stop assailants...
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That is a strawman. Gunshots obviously do pretty reliably stop attackers. However, it is quite clear that the most common stopping mechanism is not death, or incapacitation or even serious injury. The most common stopping mechanism is the attacker's decision to stop attacking based on a change in motivation from the desire to perpetrate the attack to a desire to not get shot (or shot at) any more. This is often termed a "psychological stop". There really isn't much room for debate on that topic, it has been universally accepted fact for a very long time.
But the required information is how many of the single hits were center mass, and how many of those caused the shot person to fall down to the ground by any mechanism. That is the area of dispute.
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None of those things really have anything to do with whether the force of a bullet impact is going to knock someone down.
 
Just a vernacular term, in my opinion.

Same as if I said ".45 automatic" when referring to a semi-automatic.

I don't think it's intended to signify the force of the bullet can physically knock someone down, more that the wound and shock created by the bullet causes them to fall down.

It's been used for a long time nevertheless:

y1lER5R.png
 
JohnKSa said:
.Ok, I'm going to assume that the comment about "black powder levels" was intended to be humorous and take it in that vein.

Miculek states in the video that the velocity is about 2400fps which would mean that it has only 9 times the momentum of the 45ACP instead of about 10 times :D.

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Methinks Jerry is over-stating the velocity a LOT more than he realizes. Yes...Hornaday DOES state that the 750 A-Max load is 2820 from a 24" barrel (Jerry is using 20" which would compute fairly well)....but....their catalogue numbers are wrong and they actually used 36" test barrel to reach the 2820 figure. See: https://forum.snipershide.com/threads/50-bmg-750g-amax-bullet-drop-muzzle-velocity.199182/

I've shot quite a few 750 A-Max out of an Armalite AR-50 w/30" barrel and was getting 2700'ish with max charges and can say for certain that taking 10" off of that barrel is going to reduce the velocity more than 300 fps. I DO completely agree with your statements about 'Knock-down Power' being fanciful movie and gun rag drivel....just wanted to stick up for the BMG a little by pointing out that shooting one out of such a short barrel is NOT getting the full 'flavor' of the round.:)
 
JohnKSa said:
That is a strawman. Gunshots obviously do pretty reliably stop attackers. However, it is quite clear that the most common stopping mechanism is not death, or incapacitation or even serious injury. The most common stopping mechanism is the attacker's decision to stop attacking based on a change in motivation from the desire to perpetrate the attack to a desire to not get shot (or shot at) any more. This is often termed a "psychological stop". There really isn't much room for debate on that topic, it has been universally accepted fact for a very long time.None of those things really have anything to do with whether the force of a bullet impact is going to knock someone down.
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Okay, no argument with you about "most common".
 
500 ft/lb of energy can exert 200 lb of force over a distance of 2.5 feet. Maybe the fictional scene in “A Fistful or Dollars” where Clint Eastwood absorbs several rifle rounds in a steel plate protecting his torso is actually a realistic depiction. Each round staggers him momentarily. That amount of energy exerted on an impenetrable surface could well have that effect as all the energy is delivered over a very short interval. A less capable subject could easily be put on the ground. Not thrown through the air, but put on the ground. But the human body is not an impenetrable surface and the bullet is gradually decelerated as it passes through the body. That changes the dynamic completely.
 
Just my .02. And another vote for myth.

I got hit with two 7.62x39 from an AK . One graised head ( boonie hat no helmet), and one hit the left shoulder.( No flak vest) (yes I got my butt chewed)

I didn't go down.

I got real pissed off and returned fire. Lots of it with positive results. Being the medic I treated myself and walked- with help cause it hurt, and I leaked a lot - to the med evac.
Unless it is a CNS hit - preferable to the medulla oblongata you should not go down.
 
rpenmanparker said:
Thanks for that. But the required information is how many of the single hits were center mass, and how many of those caused the shot person to fall down to the ground by any mechanism. That is the area of dispute.
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That is absolutely not the required information needed in this thread. Confusing the issue by linking a myth based in faulty physics (knock down power) with a made up term used to describe a bullet's ability to incapacitate a living target (stopping power) is not helping. They are two different things.

Knock down power simply CAN NOT be true. When we consider a living creature's structure a bullet will pass completely through it or stop inside it due to low weight or expansion. If it passes through all the energy in the world means nothing because it is being deposited in whatever is behind the target. Yes catastrophic damage is very likely, but that doesn't mean a target will be knocked over. Staggered due to the impact force and surprise, sure, but it's not going to take someone or something off its feet. You will have more "knockdown power" if you throw a cinder block at them than if you shoot them, because the force is spread widely enough to impact enough tissue to actually push a human body's mass over. Foot pounds as a unit of work actually means something at that point. Armor as seen in the video will increase the impact on a living body if it stops the bullet because all the momentum is deposited at the impact point, transferred to the armor, and then to the human body.

If the bullet is light enough not to pass through or expands enough that it stops, the velocity or mass, and thereby the energy involved are not high enough to produce "knock down power" either.

I have seen animals shot where it looks like they are being knocked over. I believe what is actually happening is a CNS hit is causing the legs to fold violently.

"Stopping power" is a very different concept that is based purely on correlative data, and can be caused by several different factors from central nervous system disruption, blood loss causing unconsciousness, and the psychological effects of being shot or avoiding being shot. Different topic, and one that has been discussed many time on THR.
 
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I've had animals fall over, DRT. It's been postulated if you hit a small enough animal
with a powerful enough projectile during a specific timing of the heartbeat, that causes
the circulation to overload pressure to the brain, causing a blackout, which, in turn, causes
the animal to drop to the ground like a sack of potatoes.

Since it does not literally "knock down" the animal, from blunt force of the bullet pushing it
over, I guess it can be argued that is not
"Knockdown Power" , but could it possibly be considered "Stopping Power"? Generally,
the animal wakes up dead, and never rises.
 
It was impossible to knock the dummy down as it was suspended from the top. Duh.
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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.
 
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