Hmmmmm. I could never figure out how a bullet that leaves a gun, has 'knock down' power. Yet, it doesn't knock down the person doing the firing. I believe that people have been blown right out of their shoes with the blast from a .44 magnum, or a shotgun. I realize that energy is being absorbed by the weapon and the shooter. But how can the shooter still be standing up, when the person shot goes down?
For every reaction there is an opposite/equal reaction?
Here is another one: I have heard that in aerodynamics, it doesn't matter whether the vehicle/craft goes through the air,l or if air is blown at the vehicle/craft; the outcome is the same.
In other words...if theyu wind-tunnel tested your vehicle...the air patterns going over and around your car would be the same asw if your car was driving through the air.
*I* think they are wrong. I think there are differences. You already know that there is a difference because the procedure is different. Therefore, there IS a difference. But is this difference a measurable difference? I have heard they so no. I think there IS.
If wind is being blown at a stationary car in a wind-tunnel test....all the airflow should be going reward, except fo the back swirl you get from the vacuum caused by the reatr of the car. But what about side drag? If your car is MOVING forward, i would think that air would be pulled with the car along the side. Also, I would think that a car in motion would cause front-end area air to plow forward and create a different flow pattern than with the test when the air is blown at a stationary car.
Also, I think the air flow might be different for under the car also. Again, with a moving car, i would expect the air to grab ahold of the underside structures and be pulled forward, and swirl around. Where, i f they instead blew air at the car while stationary, you would think the air pattern would just show as basically all traveling rearward.
In other words...if theyu wind-tunnel tested your vehicle...the air patterns going over and around your car would be the same asw if your car was driving through the air.
*I* think they are wrong. I think there are differences. You already know that there is a difference because the procedure is different. Therefore, there IS a difference. But is this difference a measurable difference? I have heard they so no. I think there IS.
If wind is being blown at a stationary car in a wind-tunnel test....all the airflow should be going reward, except fo the back swirl you get from the vacuum caused by the reatr of the car. But what about side drag? If your car is MOVING forward, i would think that air would be pulled with the car along the side. Also, I would think that a car in motion would cause front-end area air to plow forward and create a different flow pattern than with the test when the air is blown at a stationary car.
Also, I think the air flow might be different for under the car also. Again, with a moving car, i would expect the air to grab ahold of the underside structures and be pulled forward, and swirl around. Where, i f they instead blew air at the car while stationary, you would think the air pattern would just show as basically all traveling rearward.
Ziggurat
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Iamme said:
Nope, your intuition is wrong. Air getting "dragged" along by the car with real driving is the same as stationary eddys that form around the car in a wind tunnel. Relative motion is all that matters, and the two situations really are close to equivalent. Small differences come in regarding whether, for example, the finite size of the wind tunnel makes a difference (equivalent to the question of whether air drag changes when you DRIVE through a tunnel), etc.
Ziggurat
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Iamme said:
Several things to keep in mind. First, when the bullet is fired from the gun, the recoil on the gun itself means that the gun and the bullet have equal (magnitude) momentums in opposite directions. However, the gun being much more massive than the bullet, it's traveling MUCH more slowly during recoil. The person holding the gun therefore has much more time during which they can absorb the that momentum by pushing back on the gun than the person hit by the bullet, who is going to absorb that momentum really quickly. Both the shooter and the target absorb the same amount of momentum in the process, it's only the time scales that are radically different. One consequence of this is that the target doesn't have time to respond to the momentum with his muscles: he's already falling before his reflexes even kick in. The shooter, however, may already be braced for the the momentum input, and also have enough time for muscle responses to be able to do anything. The situation is somewhat similar to why it's MUCH easier to push someone over with a quick shove when they aren't expecting it. But again, the momentum transfered to both the shooter and the target (by the gun and by the bullet, respectively) are the same.
Another way to think about this is to separate the process into three different interactions: bullet-gun, bullet-target, and gun-shooter. In each pair of interactions, both the momentum transfer between the two objects AND the time scale for that transfer are the same (equal and opposite reactions). But notice that the shooter and target never interact directly, so the timescales for momentum transfer for the target do NOT need to be the same for the shooter and target.
Iamme said:
As others have pointed out, the air is slowed down underneath the car in the wind tunnel, and this is equivalent to the air being dragged when the car is driving. I did want to point out one subtlety with testing ground vehicles in a wind tunnel though. You have to have it on a rolling road,otherwise the boundary layer on the bottom of the tunnel interferes with the flow. Typically what you have is a rubber belt which moves at the same speed as the air. This forms the bottom of the working section of the tunnel. For best accuracy, the wheels of the model vehicle should rotate too.
--Terry.
Have you considered the possibility that it doesn't actually work that way, i.e., that kinetic energy isn't actually "knocking down" the person shot? I don't know, but I'm curious, and I'd be interested in hearing about documented instances of people who were "blown right out of their shoes".Iamme said:
_Q_
Re: Re: For every reaction there is an opposite/equal reaction?
This brings to mind Stephen Boyett's fantasy novel _Ariel_, where his hero knocked down several bad guys with blowgun darts. Boyett seemed rather embarassed about this in his afterword to the electronic edition, years later.
I've read that this is a myth (I think it was in a chapter in _Murder Ink_, written by a policeman or other expert and aimed at prospective mystery writers, but I am not in a position to verify this)._Q_ said:
This brings to mind Stephen Boyett's fantasy novel _Ariel_, where his hero knocked down several bad guys with blowgun darts. Boyett seemed rather embarassed about this in his afterword to the electronic edition, years later.
You watch too much television. Bullets do not blow people out of their shoes. That's Hollywood. If you don't believe me, go fill up a gallon jug with water and shoot it with a .44 magnum. The jug doesn't go flying backwards, and neither will a human being.
Abdul Alhazred
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Iamme said:
A person hit by a .44 magnum doesn't "go down" because of sheer momentum, but because of the trauma caused by the bullet.
By rhe way, have you ever fired a .44 magnum? You can break your arm from the recoil if you don't do it just right.
Badger
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With regards to the "blown out of their shoes" precept, I think that's pure Hollywood.
Watch the hunting channel sometime. You can see many real life examples of bullet/shotgun impacts on many different sized targets (typically, shotgun on turkey, and rifle on deer, though they have many other hunts as well).
As an example of your .44 magnum, you'll want to watch the muzzle loader hunts of wild boar.
I have shot quite a few deer at a variety of distances, with my .308, and have not witnessed anything like the "blown out of their shoes" effect.
I shoot a high velocity round at large-man sized animals, and only had the bullet pass through my target animal on 2 occasions. On the first occasion, it took the deers innards with it as the whole mass exited its abdomen. And on the second occasion, it took a fist sized chunk of skull/brain with it as it exited the deers head. Invariably, the animal has, at most, flinched when hit and has not been thrown off balance by the bullet impact.
The "knock down" power you talk about pertains more to ability of the target to function after being struck. The internal damage done is a result of the momentum of the bullet being transferred to the target. Rounds that are deemed to have "knock down" power are designed to transmit their energy to body mass by shredding it or mashing it with a shockwave. To shred tissue, the bullet is designed to fragment on impact, breaking up into smaller pieces that get stopped in the tissue. To mash tissue, the bullet is designed to expand in diameter on impact, causing a shockwave that jellifies tissue.
There is much more to ammunition design, ballistics, and gun design than that, but these are a few things applicable to this discussion.
Watch the hunting channel sometime. You can see many real life examples of bullet/shotgun impacts on many different sized targets (typically, shotgun on turkey, and rifle on deer, though they have many other hunts as well).
As an example of your .44 magnum, you'll want to watch the muzzle loader hunts of wild boar.
I have shot quite a few deer at a variety of distances, with my .308, and have not witnessed anything like the "blown out of their shoes" effect.
I shoot a high velocity round at large-man sized animals, and only had the bullet pass through my target animal on 2 occasions. On the first occasion, it took the deers innards with it as the whole mass exited its abdomen. And on the second occasion, it took a fist sized chunk of skull/brain with it as it exited the deers head. Invariably, the animal has, at most, flinched when hit and has not been thrown off balance by the bullet impact.
The "knock down" power you talk about pertains more to ability of the target to function after being struck. The internal damage done is a result of the momentum of the bullet being transferred to the target. Rounds that are deemed to have "knock down" power are designed to transmit their energy to body mass by shredding it or mashing it with a shockwave. To shred tissue, the bullet is designed to fragment on impact, breaking up into smaller pieces that get stopped in the tissue. To mash tissue, the bullet is designed to expand in diameter on impact, causing a shockwave that jellifies tissue.
There is much more to ammunition design, ballistics, and gun design than that, but these are a few things applicable to this discussion.
knock down nothing
The .44 Magnum is one of the most powerful weapons designed to be used with at least one hand. But the energy (half the mass velocity-squared product) and the momentum (mv) is trivial in comparison with that available from rifles and other shoulder fired weapons. ( Just a quick fact check, the 44 gets 1000+ ft-lbs of muzzle energy, several rifles over 5000, one listed at just under 8000)
The title of this post is the title of an article in a '70's era edition of Gun Digest. The author took a deer sized box of dirt standing on 2x4 legs and fired into it with rifles at arms length ranges. The 'deer' never fell down, or even moved significantly.
Interestingly a significant fraction of the recoil the shooter feels is due to accelerating the powder charge, so the shooter is getting the result of more 'mv' than the bullet is carrying.
The .44 Magnum is one of the most powerful weapons designed to be used with at least one hand. But the energy (half the mass velocity-squared product) and the momentum (mv) is trivial in comparison with that available from rifles and other shoulder fired weapons. ( Just a quick fact check, the 44 gets 1000+ ft-lbs of muzzle energy, several rifles over 5000, one listed at just under 8000)
The title of this post is the title of an article in a '70's era edition of Gun Digest. The author took a deer sized box of dirt standing on 2x4 legs and fired into it with rifles at arms length ranges. The 'deer' never fell down, or even moved significantly.
Interestingly a significant fraction of the recoil the shooter feels is due to accelerating the powder charge, so the shooter is getting the result of more 'mv' than the bullet is carrying.
I would accept the reason that a person falls when hit by a bullet is apt to relate to damage- for example a leg wound may make the leg permanently unable to support the victim, by damage to bone, muscle or tendon.
There is also the question of the victim's momentum in the instant before he is struck; he may be running towards, or away from the shooter, on one foot (or none, in mid stride), turning, unbalanced etc. By contrast, the shooter is braced and stable. I suspect someone running and firing a large gun one handed might be knocked off balance by the recoil, even though he suffers no traumatic damage. (Try running fast, turning and throwing a brick simultaneously. There is a high probability of falling on your butt.)
There is also the question of the victim's momentum in the instant before he is struck; he may be running towards, or away from the shooter, on one foot (or none, in mid stride), turning, unbalanced etc. By contrast, the shooter is braced and stable. I suspect someone running and firing a large gun one handed might be knocked off balance by the recoil, even though he suffers no traumatic damage. (Try running fast, turning and throwing a brick simultaneously. There is a high probability of falling on your butt.)
This is all very fascinating.; I have been reading all the posts and you all sound quite knowledgeable. I MUST have watched too many movies, I guess.
I DID indeed fire a .44 magnum about 20 years ago. I believe I did it one handed. I was very apprehensive to try this as I heard about the broken wrist/broken arm stories.
In the movies, what made them come up with the cartoonish effect of people being lifted and propelled rearward, when shot with a powerful gun...if there isn't some truth to this? If the bullet was large, and a hollow point...I can see how the 'force' could be transfered into the body, more so than if a pointy bullet were used.
What would happen to a guy shot close range with a shotgun, if he was wearing a bullet proof vest?
Regarding the air testing: I think what threw me off about side drag was that I was envisioning blowing air at an ever so slight angle at the side of the car, and picturing all air being deflected rearward. But upon more careful thinking, the air would be head on, and now I can better see how the drag effect could occur in both the vehicle in motion and the vehicle stationary with wind tunnel.
Sorry about typos in thread starting post. I was fighting an on-screen nuisance 'pop-up', when my post took prematurely.
I DID indeed fire a .44 magnum about 20 years ago. I believe I did it one handed. I was very apprehensive to try this as I heard about the broken wrist/broken arm stories.
In the movies, what made them come up with the cartoonish effect of people being lifted and propelled rearward, when shot with a powerful gun...if there isn't some truth to this? If the bullet was large, and a hollow point...I can see how the 'force' could be transfered into the body, more so than if a pointy bullet were used.
What would happen to a guy shot close range with a shotgun, if he was wearing a bullet proof vest?
Regarding the air testing: I think what threw me off about side drag was that I was envisioning blowing air at an ever so slight angle at the side of the car, and picturing all air being deflected rearward. But upon more careful thinking, the air would be head on, and now I can better see how the drag effect could occur in both the vehicle in motion and the vehicle stationary with wind tunnel.
Sorry about typos in thread starting post. I was fighting an on-screen nuisance 'pop-up', when my post took prematurely.
EdipisReks
Custom Title
Re: Re: For every reaction there is an opposite/equal reaction?
bull$hit. 44 magnums are pussy cats. have you ever actually fired one? most 44 magnums are very large guns, and thus don't recoil heavily at all. i find full power 10mm auto rounds fired from 1911's to be much more punishing, but even those are totally controllable with a little bit of concentration, even doing double and triple taps. you can get repetitive stress injuries from firing guns, but the only way you are going to get a broken arm from a 44 magnum is if someone hits you with the gun physically.
Abdul Alhazred said:
bull$hit. 44 magnums are pussy cats. have you ever actually fired one? most 44 magnums are very large guns, and thus don't recoil heavily at all. i find full power 10mm auto rounds fired from 1911's to be much more punishing, but even those are totally controllable with a little bit of concentration, even doing double and triple taps. you can get repetitive stress injuries from firing guns, but the only way you are going to get a broken arm from a 44 magnum is if someone hits you with the gun physically.
EdipisReks
Custom Title
Re: knock down nothing
check out the 700 Holland and Holland. several loads will exceed 12k.
tedly said:
check out the 700 Holland and Holland. several loads will exceed 12k.
EdipisReks
Custom Title
Badger said:
12 gauge to a 3a+ vest (probably 2a will stop it, as well) at point blank with 00 shot is perfectlly survivable, though there will be heavy bruising and your heart rhythm might be screwed up for a couple days. it's the same with any heavy caliber handgun round. a standard slug will probably be stopped, but cracked ribs will be expected. a sabot .50 slug will most likely penetrate. it all really depends on the ammo, what you are wearing, and the distance.