Steve Smith
New member
I voted for "hurtled across the room" hoping that others here would be saying the same, all of us "in the joke." Oh well.
Will a .45acp knock you down?
- Thread starter Brasso
- Start date
Zundfolge,
Good find on the formula, but it's not applicable to the problem. It's true that a 150# shooter firing a .45 in space would be accelerated only to a speed of about 2-1/4 inches/second. If it was applicable, we would be seeing .50 BMG cartridges in handguns!
None of the poll choices are descriptive of what actually happens. Lift off never occurs -- that is a special effects fantasy.
A better physics description of the problem is a torque. The 150# target is assumed to be standing upright (feet parallel), and let's say his COM is at 4 feet above the ground. The muzzle energy of the 230 gr. slug is about 370 ft lbs, which is converted to a force applied to his COM of 92.5 pounds on the 4' lever tending to rotate the body about the axis of the feet. The earth supports all but a small fraction of the target's weight the entire time, and the slug never lifts him up-up-and-away at all.
Turns out that the problem can be empiracally simulated without shooting anybody and without resorting to half baked opinions.
A regulation baseball weighs about 5 ounces, and when at a velocity of about 59 mph has equivalent energy to a .45 slug. You need: a baseball, catcher's equipment, a 5' to 6' guy who will weigh 150# wearing the catcher's equipment, an accurate pitcher who can consistently hit the target with a 59 mph ball, a baseball chronograph, a blindfold, and a 2x4 board.
After the target is suited up, tape an "X" 4' above the ground. Have him stand relaxed and blindfolded with his heels against the 2x4. He won't see or hear the pitch coming so he won't flinch or brace himself. One accurate pitch, and what do you think will happen...?
Of course, you could just have somebody punch the target on the "X" with a force of 92.5#, but what fun would that be? You'd only need the chest protector, blindfold, 2x4, and maybe a boxing glove though.
Good find on the formula, but it's not applicable to the problem. It's true that a 150# shooter firing a .45 in space would be accelerated only to a speed of about 2-1/4 inches/second. If it was applicable, we would be seeing .50 BMG cartridges in handguns!
None of the poll choices are descriptive of what actually happens. Lift off never occurs -- that is a special effects fantasy.
A better physics description of the problem is a torque. The 150# target is assumed to be standing upright (feet parallel), and let's say his COM is at 4 feet above the ground. The muzzle energy of the 230 gr. slug is about 370 ft lbs, which is converted to a force applied to his COM of 92.5 pounds on the 4' lever tending to rotate the body about the axis of the feet. The earth supports all but a small fraction of the target's weight the entire time, and the slug never lifts him up-up-and-away at all.
Turns out that the problem can be empiracally simulated without shooting anybody and without resorting to half baked opinions.
A regulation baseball weighs about 5 ounces, and when at a velocity of about 59 mph has equivalent energy to a .45 slug. You need: a baseball, catcher's equipment, a 5' to 6' guy who will weigh 150# wearing the catcher's equipment, an accurate pitcher who can consistently hit the target with a 59 mph ball, a baseball chronograph, a blindfold, and a 2x4 board.
After the target is suited up, tape an "X" 4' above the ground. Have him stand relaxed and blindfolded with his heels against the 2x4. He won't see or hear the pitch coming so he won't flinch or brace himself. One accurate pitch, and what do you think will happen...?
Of course, you could just have somebody punch the target on the "X" with a force of 92.5#, but what fun would that be? You'd only need the chest protector, blindfold, 2x4, and maybe a boxing glove though.
Freedom in theSkies
New member
Depends on which end of the barrel you are on...
M
M58
Guest
No.
Just watch any number of in-car videos from police cruisers. The best was a Texas Trooper(P220) shooting a suspect with a knife; solid body shots; the suspect kept moving forward; had to be wrestled to the ground.
.45 ACP the Urban Myth.
Just watch any number of in-car videos from police cruisers. The best was a Texas Trooper(P220) shooting a suspect with a knife; solid body shots; the suspect kept moving forward; had to be wrestled to the ground.
.45 ACP the Urban Myth.
I am NOT claiming that this is common or that if I shot someone with a .45 I'd expect him to fall down . . . . but . . . . George Hill has posted to the effect that he was once knocked flat on his back when shot from a .45 while wearing body armor. He wasn't expecting the shot and it was a total surprise, but . . . . . still.
Geez, Doc!!! I'm still wipin' the tears from my eyes!!! If laughter is good for the health, I'm good for another 5 or 6 CENTURIES.
Anyway, I remember reading on a site not too long ago (read - believe with a pound or two of salt) that the typical 230 gr wad of lead that your typical 45 spits out is really no different than the force applied by a [I think it was a 10 LB mass] dropping [I think it was 1"]. In other words - not much. However, the physical REACTION of the target can significantly alter the results. Said target may scare themselves airborne.
In another context... Ever gone out huntin' Bambies? Kinda popular this time of year... If you do, you'll probably use something like a 30-30, 30-06, 308 or whatever. Damn sight more powerful than a 45. Bambie is usually smaller than the 90% human, yet doesn't fly when hit...
Anyway, I remember reading on a site not too long ago (read - believe with a pound or two of salt) that the typical 230 gr wad of lead that your typical 45 spits out is really no different than the force applied by a [I think it was a 10 LB mass] dropping [I think it was 1"]. In other words - not much. However, the physical REACTION of the target can significantly alter the results. Said target may scare themselves airborne.
In another context... Ever gone out huntin' Bambies? Kinda popular this time of year... If you do, you'll probably use something like a 30-30, 30-06, 308 or whatever. Damn sight more powerful than a 45. Bambie is usually smaller than the 90% human, yet doesn't fly when hit...
Blackhawk,
One of your basic problems is that you are making the assumption that the collision is inelastic.
Elastic collisions aren't often covered in physics courses because they are very complex and the mathematic equations governing them are often intractable.
However, very simply, the baseball dumps its full load of energy very abruptly since neither it nor its target deforms appreciably (an almost inelastic collision) while the human body when hit by a bullet deforms significantly (extremely elastic collision). All of the damage done by a bullet as it penetrates flesh is a function of the energy of the bullet and as such, it requires energy. In other words, the penetration and damage uses some of the bullet's energy. The energy used to damage flesh and bone and to deform the bullet is no longer available to be converted into momentum (push).
This also accounts for why the man hit while wearing a bullet proof vest noted a push--the bullet imparted nearly its full energy load very rapidly into the vest. Even so, it isn't likely that a handgun bullet will knock down a vest wearer, unless he is caught off balance as the momentum imparted is quite small.
One of your basic problems is that you are making the assumption that the collision is inelastic.
Elastic collisions aren't often covered in physics courses because they are very complex and the mathematic equations governing them are often intractable.
However, very simply, the baseball dumps its full load of energy very abruptly since neither it nor its target deforms appreciably (an almost inelastic collision) while the human body when hit by a bullet deforms significantly (extremely elastic collision). All of the damage done by a bullet as it penetrates flesh is a function of the energy of the bullet and as such, it requires energy. In other words, the penetration and damage uses some of the bullet's energy. The energy used to damage flesh and bone and to deform the bullet is no longer available to be converted into momentum (push).
This also accounts for why the man hit while wearing a bullet proof vest noted a push--the bullet imparted nearly its full energy load very rapidly into the vest. Even so, it isn't likely that a handgun bullet will knock down a vest wearer, unless he is caught off balance as the momentum imparted is quite small.
Robby from Long Island
New member
Hey Snowdog,
When I finished boot training in 1960, the first thing I did when getting home was telling my father that shooting a guy in the thumb with a .45 would knock him down.
I remember him staring at me saying, "you are as dumb as you look".
Wonder when that thumb routine first started?
Safe shooting.
When I finished boot training in 1960, the first thing I did when getting home was telling my father that shooting a guy in the thumb with a .45 would knock him down.
I remember him staring at me saying, "you are as dumb as you look".
Wonder when that thumb routine first started?
Safe shooting.
JohnKSa,
Wonderful post!
You're right in that the deformation energy isn't available for "push", but it contributes in other ways to the net effect of somebody being shot COM.
Some of us (me included) have been "lucky" enough to be knocked unconscious (fist in my case) unexpectedly without ever losing their balance. That's because the brain stem still has all it needs to keep the muscles doing what they were doing before despite the loss of conscousness. However, that doesn't include reacting to obstacles, etc. That's the headless chicken drill. In my case, I came to about 10' from where I was slugged, still on my feet, turned 180 degrees, and wondering what happened.
Nobody knows exactly what brain and neurological effects occur when someone is heart shot with a .45, so it's all guess work regardless of the qualifications of the opinionator. In contemplating and discussing my knock out with experts over the last 40 years, the concensus seems to be that I would have fallen over if anyone had given me a slight push and surely if the terrain had been uneven as I staggered those 10'. Maybe, maybe not.
The point is, total loss of blood pressure from being heart shot results in loss of consciousness within about 1/2 second, and the residual of the 90# push give or take "elastic" losses is more than a slight push. The observed jumping back, which looks an awful lot like it's caused by the bullet impact, may be a brain stem reaction to losing balance and the legs extending. The comprehensive technical analysis of what happens in any given case is impossible because it's not replicable. However, enough independent eyewitnesses have reported seing COM shot humans "falling backwards" that the phenomenon cannot be dismissed as imagination.
If someone is standing with their heels against an obstacle, and something immediately in front of them startles them greatly, they'll fall backwards even without being shot. They'll also fall backwards if they receive an unexpected shove of relatively low energy. We can't prove exactly what happens, but we can simulate enough of it to reproduce historically reported effects.
Wonderful post!
You're right in that the deformation energy isn't available for "push", but it contributes in other ways to the net effect of somebody being shot COM.
Some of us (me included) have been "lucky" enough to be knocked unconscious (fist in my case) unexpectedly without ever losing their balance. That's because the brain stem still has all it needs to keep the muscles doing what they were doing before despite the loss of conscousness. However, that doesn't include reacting to obstacles, etc. That's the headless chicken drill. In my case, I came to about 10' from where I was slugged, still on my feet, turned 180 degrees, and wondering what happened.
Nobody knows exactly what brain and neurological effects occur when someone is heart shot with a .45, so it's all guess work regardless of the qualifications of the opinionator. In contemplating and discussing my knock out with experts over the last 40 years, the concensus seems to be that I would have fallen over if anyone had given me a slight push and surely if the terrain had been uneven as I staggered those 10'. Maybe, maybe not.
The point is, total loss of blood pressure from being heart shot results in loss of consciousness within about 1/2 second, and the residual of the 90# push give or take "elastic" losses is more than a slight push. The observed jumping back, which looks an awful lot like it's caused by the bullet impact, may be a brain stem reaction to losing balance and the legs extending. The comprehensive technical analysis of what happens in any given case is impossible because it's not replicable. However, enough independent eyewitnesses have reported seing COM shot humans "falling backwards" that the phenomenon cannot be dismissed as imagination.
If someone is standing with their heels against an obstacle, and something immediately in front of them startles them greatly, they'll fall backwards even without being shot. They'll also fall backwards if they receive an unexpected shove of relatively low energy. We can't prove exactly what happens, but we can simulate enough of it to reproduce historically reported effects.