Posted on 10/02/2007 9:15:49 AM PDT by 7thson
Hey, I got a question for all the firearm experts/enthusiasts on Free Republic.
Speaking to my grandson recently - he is 16 - he told me a episode of Mythbusters where the look at the 'myth' shown in movies when a person gets shot they get blown back. The Mythbuster people concluded it was false by shooting a dead pig and a dummy. Also - and this stood out to me right away - they said that according to Newtons law - every action has an opposite reaction - that when the person gets blown back it would mean the shootist would get blown back the opposite direction.
Now please correct me if I am wrong because I do not know much about firearms. But I told my grandson that mythbusters got it wrong. First, I said that certain firearms were developed for the sole purpose of putting people on their arse. And two - they got the law wrong. I said that when you fire a gun the reaction is the recoil. And that when the bullet hits the person, the opposite reaction is getting pushed back.
Can someone tell me if I am wrong or right. Also, does anyone know where I can link to the political belief test that indicates whether someone is a conservative, liberal, Stalinist, etc?
I dont think there is enough mass in a bullet or shot to physically move someone like in the movies is what their summation was.
The bullet delivers X foot-pounds of energy to the target, and that may be enough to unbalance someone or spin them around. Most of the reaction to a bullet hit is muscle retraction, which can cause some wild gyrations. A conventional small arms bullet doesn’t have enough kinetic energy to lift someone off their feet, but a .50 caliber Browning slug might encounter enough resistance in the body to give up enough energy to do that.
it’s not “mass” you’re worried about; it’s mass times velocity squared. Can add up to a lot of foot-pounds.
Law enforcement buddies, as well as military buddies, have confirmed to me that people who are shot with bullets are blown backwards, sometimes significantly so.
People certainly aren't sent flying backwards from being hit by a .38 round at 20 yards like they do in the movies.
The premise of the Mythbusters segment was whether the force of a shot could make a human body fly backward through a window, as in a stereotypical cowboy “shoot ‘em up.” Their tests indicated no, and they used up to a .50 cal.
What did the video show?
7thson,
Sorry, but it is a myth. For every action there is an equal reaction. That is true. But when continplating force, we must consider mass. The force of a bullit is large for it’s mass. The reason? Speed! That re-coil you feel when firing a .357 is the reaction from the blast of the charge. A bullit stopping quickly in a human body indeed does transfer that energy. However, the body is much more massive than the bullit and abosrbs this energy internally (organs get moved, tissue tears, etc.)
Consider, in terms of dangerous kinetic energy, what is more lethal. A 200 car freight train fully loaded moving at toward you at 10 MPH or a .357 fired at you at 10’.
You will not stop the train no matter what you do. You will propbably stop the bullit. But the impact force will not knock you down.
There are movies on the internet showing what happens to a terrorist when he gets hit with a .50cal sniper shot. These are single bullet hits and the bodies get tossed by the force of the impact.
The mythbusters probably used a .22
Take the .44 Mag for example.
Despite its legend as a real powerhouse, it's important to understand that the .44 Mag is not really a "powerhouse" in hunting cartridge terms. The "standard" fast factory load uses a 240-grain bullet at 1,350 fps for 971 ft-lbs of energy
For every action, there is an equal and opposite reaction. If there are 971 ft-lbs of energy imparted to the bullet, then there are 971 ft-lbs of energy imparted to the shooter's hand.
When the bullet strikes it's target, assuming it is stopped by the target, then 971 ft-lbs are imparted to the target.
Now, if 971 ft-lbs is not enough energy to throw the shooter back 20 feet, then it is not enough energy to throw the victim 20 feet either.
Only when it is a really large bullet. The energy of the bullet is restricted to the impact area. The damage around the entrance and exit, other than by bullet and bone fragmentation is cause by the vacuum of the bullet. Flesh is soft. I watched the work by the myth busters it is mostly correct.
I think for most bullets in most situations, Mythbusters got it mostly right.
While some bullets carry a great deal of energy, the other element to consider is how *fast* and how completely that energy is imparted in the target.
Highly frangible bullets will decelerate quicker and deliver more force over a shorter time. A solid lead, or better a jacketed bullet will travel further and decelerate over a longer period of time, spreading that energy over more time.
But in any case, the effect is not going to be so much that it will pick up somebody and toss them backward through a window or anything like that.
Some people that’ve been shot (I’m not one of them) say that it’s more or less like being whacked hard with a baseball bat. It certainly may make you fall down, but not fly through the air.
No, the person does not fly backwards. Go watch the video of a guy shooting himself in the chest point blank to test a bullet proof vest. He does not "fly" backwards. Granted it was a .38. Go watch the youtube video of the marine that got hit by a sniper. He had on body armor and was not sent flying back. In both of those cases, 100% of the bullet's kinetic energy was transfered to the mass of the human body. I can't speak for .50 cal or 12ga slugs. I can say that I have shot a 195lb deer with a 12ga slug at 50 yards and it did not knock the deer down. The deer jumped, ran 20 yards and died with the slug still inside. This is one of many deer I have shot and I have yet to send one flying backwards (away from me) when they were hit. They usually jump first go a few steps and lay down to die.
physics is a real bitch.
Now, I was under the impression that a firearm was built for the US Army during the Philippine Insurection back in the 1900's that would knock down on their arse who they were fighting because the natives were so popped up on native drugs that ordinary pistols did not stop them. Is this true?
I guess the myth - remember I did not watch the episode - is being knocked down and back several feet. Now, maybe a gun will not knock you back 10-20 feet but are there not firearm caliber that once you are hit, will put you down?
Also, anyone know of a link for that political belief test?
I’ve never been shot and I’ve never been hit by a baseball bat. Lucky, I guess. 8-)
Agreed, but we are talking about a .22 or a .44 like in the old western movies.
The myth was the body flying backwards not falling down.
Umm... K? Am I refuting that somehow?
depends on the caliber of the round and the type of round.
You get hit with a .22 you’re body is not going to go backwards
You get hit with a .45 you’re going to go back and down.
I reckon it would depent in no small amount upon whether the bullet exits the body or not. if it does not exit the body, then it’s entire energy is transferred to the body and the mass/acceleeration thingie kicks in.
if the bullet goes through the body, then some of the energy is absorbed by the body, and the remainder remains with the bullet.
there’s a classic picture of a bullet passing through an apple. the debris etc., is such that if you didn’t see the projectile in the pic, you couldn’t tell from which direction it came.
Actually, you would probably be moved a greater distance with a baseball bat. The surface area impacted would be considerably greater than a conventional rifle shot. Because there would be no penetration of being hit with a baseball bat the body effectively absorbs the impact causing motion in the same direction as the hit. Had "MythBusters" done this amatuer experiment with a bullet proof material covering the hog their results would have probably been different.
To oversimplify slightly: if it knocked down the victim, the recoil would knock down the shooter as well.
(”Knocked down” as in “blew him off his feet”, not “caused enough damage he couldn’t stand up”.)
Some observations:
There is a real effect that people think they are supposed to fall back or fall down when they get shot. People do this not because of the physics of the impact, but because of their muscle reaction, conscious or subconscious. The movies have had a big effect on this.
Recoil is comparable to “knockdown” power (assuming the bullet delivers all its energy to the target, and does not carry thorough with much energy remaining.) However, keep in mind that recoil is usually anticipated and braced against, while a bullet impact is not.
Imagine a “bullet catcher” weighing 200 pounds (Say, a steel plate on little car on rails). It is hit by a bullet weighing 1/10th pound (a 700 gr. 50BMG - conversion is 7000 gr./lb.) at 2600 feet per second, and all the energy is transferred to the target. The momentum of the bullet is transferred to the target, which weights 2000 times as much. Thus, the target will end up moving backwards at 1/2000th the velocity of the bullet, or 1.3 feet per second, or about 1 mph, which is a very SLOOOW strolling speed. But enough to make a guy fall backward, when he has just been traumatized.
Didn’t JFK get pushed forward when he was shot?
Under that condition (perfect sternum hit, well-supported by skeletal structure), the impact energy is optimally (but still imperfectly) converted into a push backwards. This push will indeed be a push back, but far from a “thrown back off his feet” kind of push.
We’re so used to being stable on our feet that we hardly consider what happens when we’re not. Think about the body mechanics: a slight reward push will throw center of gravity far enough off-center that you’ll fall ... and your legs being essentially long hard levers with a single stiff joint in the middle, the fall will push the torso & head WAY off center - resembling “thrown back”. Go ahead, try it now: stand up, lean back slightly, and see how you fall - your head (when you wake up) will be around 6’ from where it started, even though you only initially moved a couple inches.
Upshot: any “thrown back” imagery anywhere close to real will have far more to do with gravity & body mechanics than ballistic impact.
Penn & Teller covered that in their book “How To Play With Your Food”. The terminal ballistic behavior is counter-intuitive, and they demonstrate it.
You get hit with a .45 you’re going to go back and down.
And down not because of the impact, but because of the fact that you are wounded seriously, and probably want to take cover. A 45 ACP has 1/3 the mass, and less than half the velocity of a 50 BMG, so it has the same effect as being hit by a bus that is going about 2 inches per second (and stops after it hits you.)
I am saying that the myth they were testing was the body flying backwards as it gets filled with lead, not just falling down. I was not refuting what you were saying because what you said is what they proved. The mass of the bullet is not sufficient to make a body fly backwards unless the guy shooting was also flying in the other direction.
Sorry for the confusion.
That was the one problem with the Mythbusters setup. They didn’t test to see if the bullet could destabilize a 6-ft structure so it would topple over, they hung the pig from a hook and checked if it would be pushed off the hook. There was friction to overcome, and the bullet didn’t have the force to overcome that friction.
Still, they were correct that the same force tries to knock down the guy shooting. And in fact, if you stand with your feet together straight up with your heels touching a small board so you can’t step back, and you shoot a good-sized rifle, you will end up falling backwards.
A person who is shot and isn’t expecting it might therefore fall backwards because they wouldn’t step backwards to balance themselves.
But the force of a bullet, even stopped by kevlar, is less than the force of a fastball. It could knock the catcher over if the catcher didn’t adjust to receive the pitch.
Having been shot once (7.62x39 through the right shoulder), it hurt like hell, but didn’t knock me down or even spin me around. However, the first time I ever fired a .50BMG Barrett, I did it standing (on a dare),it knocked me flat on my ass.
To make it more complicated, not all of the energy of the bullet is transferred to the target all the time. If it penetrates the target there will be residual energy. If not, not.
Can a shooter get knocked down by recoil? You better believe it, I certainly have been. First time I shot a 12-gauge I was standing on a slick surface and my feet went out from under me. My brother thought it was funny to see me on my butt but I managed to keep the muzzle downrange and out of the mud. Too many witnesses to shoot him at the time, dang it.
I mention that to indicate how many variables there are in shooting in the real world. Shooting a fixed target in a laboratory isn't like shooting a crack-maddened mime on a unicycle when you're on roller skates yourself. At least I don't think so. Never tried it.
If you’ve ever shot a steel plate match, it’d be pretty obvious that Mythbusters got it right. 4-foot pepper poppers have to be balanced pretty close to vertical for even a 230gr +P .45ACP to knock it down. That’s a steel plate weighing in the neighborhood of 35-40 pounds, vertical, on a rotating axis located 2-4 feet below the area of impact, with 100% of the bullet force being transferred to the plate. Twist the set screw a few turns and even a .45 won’t knock it back. 9mm shooters learn about this phenomenon quickly since the .45’ers seem to think the joke never gets old.
Likewise, as another poster noted, I’ve shot deer — weighing anywhere from 80-130lb — with a .50 cal 350gr muzzleloader (about 1500 ft/lb), with a 12gauge shotgun slug at about 1500 ft/lb, and with a .270 (140gr) at about (2000 ft/lb). All of them broadside. None even fell sideways—they all just take a step or two and then die. If those extra heavy / slow or light/fast bullet combinations can’t blow a normal sized deer back, it won’t do it to a person.
A friend of mine that served in Somalia said that one of the problems they faced when shooting the bad guys was that they didn’t know that they were supposed to fall down and die like on TV or movies!
They’d get shot and keep on moving.
Having taken the full blast from a 16 gauge shotgun with #4 birdshot (152 bb’s) at point blank range in the chest, I assert it did not blow me backwards. It did hurt like hell and leave some nasty scarring however. Had I had a solid steel shield on my chest, I would not have the scarring, but would have been “pushed” by the round’s force.
I am happy to be here and be a FReeper too.
Kinda like the jerked tablecloth.
here’s a link to a site that does experiments on penetration, if it might be of any interest/help:
http://theboxotruth.com/
Whaddya mean? It never does get old!
Well, I think it's funny...
As for the political test you inquired about:
Simply google political test and be ready to look at many.
Here’s 1 example.
http://www.politicalcompass.org/
They need to change out the ball ammo for semi-jacketed rounds... hollow points if possible. Unless they’re shootin’ at other armored troops.
Heard that story before, too, long ago. My uncle was usin’ an M1 Carbine, shooting at a Jap. He said he could see the puffs of dust coming off of him where he was hitting - and the Jap just kept runnin’! Then the guy with the BAR got him...
I think that is a universal cry of all troops: “Bigger guns! We need bigger guns! Big ‘effin’ guns!”
I don’t know if I’ve ever heard of US troops being completely satisfied with their weapons.
This is correct. The energy recieved cannot be more than the energy transmitted.
Watch some of those old WWII newsreels from the D Day invasion. Soldiers who are shot simply drop. No standard issue military small arm has enough energy to knock someone backwards.
L
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