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Old May 11, 2005, 09:16 AM   #1
Doug.38PR
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can .45 caliber knocksomeone off their feet?

I've heard it said and read that the .45 caliber bullet is capable of lifting a man off his feet and knocking him back. Which is why, I'm told, the military for years (and among the men still do even though polititians don't) prefered the .45 auto rather than the .38 Army Special or the current .9mm Berretta. If an enemy soldier is charging you with a bayonet for instance a .9mm would kill them but they still might be able to lean into you with the bayonet or knife whereas a .45 would knock them back.

Is this true? (forget hollow points and glazers and all these modern bullet types. I'm talking about the plain LRN or FMJ)

I was told by a few others that this is a myth that if the gun doesn't knock you back from your end, it's not going to knock the man your shooting down either unless you have a hollow point or Magtech or some special bullet that does some blowing up or ripping and tearing at the flesh.
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Old May 11, 2005, 09:19 AM   #2
XavierBreath
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can .45 caliber knock someone off their feet?
No.

Unless you are shooting at plastic army men.
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Old May 11, 2005, 09:29 AM   #3
Ben Swenson
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No.

As respectable a cartridge as .45ACP is, it does not knock people off their feet, or automatically throw people through plate glass windows, or kill through near misses or anything else like that. Doesn't matter if you're using FMJ, LRN, JHP, EFMJ, JSP, AP, Glaser, MagSafe, EXTREEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEME SHOCK or cast resin bullets. Just doesn't do it.

It punches nearly half inch holes in stuff, though. That counts for something, right?
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Old May 11, 2005, 09:52 AM   #4
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Any firearm with a bullet capable of knocking someone off their feet would have the same effect on the shooter.
This is a straight momentum transfer issue (bullet energy is not involved).
Mass x velocity. A 230 grain bullet at 900 feet per second will make a 160 pound person 160 pounds x 7000 grains/pound = 1,120,000 grains move at 900 ft/s * 230 gr / 1,120,00 gr = 0.18 feet per second. A 2 mile an hour walk (very slow) is about 2.9 feet per second.

Only a hit to the central nervous can cause the victim to fall to the ground. Hitting the motor portions of the brain (including the brainstem) and severing the upper portions of the spinal cord are required.
Not fly through the air, just fall were they are.

Only in Hollywood do shooting victims fly through the air and through windows.
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Old May 11, 2005, 09:54 AM   #5
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Remember Newton's laws, the one that says that for every action there's an equal and opposite reaction. The force that the bullet applies to the target is never going to be any greater than the recoil force that the gun has. So, if shooting the gun does not knock you off of your feet, the bullet isn't going to knock the adversary off of his feet, either.

Now, I've been knocked flat by a shotgun's recoil -- first time I shot one when I was 12. That proves that a shotgun actually can do it. But that's a shotgun, a different animal than a handgun.
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Old May 11, 2005, 09:59 AM   #6
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Only in movies.

However racking the slide on a shotgun will make bad guys stop and surrender.
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Old May 11, 2005, 10:55 AM   #7
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'racking the slide' LOL LOL . I remember an incident where a cop was in the back room of a store waiting for possoble BGs . One came in, the cop ID'd himself and immediately was shot at !! That's as funny as those that think the BGs will wait for you to finish in the bathroom before they act .Most of the BGs are high on drugs or alcohol....But knocking a person ove r ? just work out the numbers , it's just physics. There was a wonderfull video from a cruiser where a cop shot a BG with a 45 [in the stomach] with little effect.You can hear the cop say that he thought a 45 would have more effect than that !! Only hits ,only good hits and there is no sure thing so keep shooting until he's no longer a threat !!!
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Old May 11, 2005, 12:42 PM   #8
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I am continually astounded at the people who believe that bullets knock people down.

If you hit someone in a bone support (like their pelvis) with something hard enough to shatter the bone, someone might fall down - but they may still be capable of shooting back.

If you hit someone high in the spine (above the shoulder blades), and you sever the spine, that would cause someone to fall down (and stop shooting).

Bullets through the brain are less predictable - people have been shot in the brain with 38 +P rounds and still managed to keep fighting.

Don't worry about knocking them down. Worry about putting the rounds you have in the right places. A 22 through the femoral artery may not put someone down immediately, but they're probably going to die before the ambulance gets there.
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Old May 11, 2005, 02:09 PM   #9
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I have a question though. The recoil of the gun is counterbalanced by the bullet travelling the opposite direction.

But what if the bullet stayed stationary and was fired...wouldn't the force of recoil be horrendous? What I'm getting at is I don't believe the forces are equal here. I would think being hit by a .45 bullet would have a lot more force than just the simple recoil felt at the gun...no?

So say the recoil at the Kimber is more like 10ft/lbs, and the bullet has what...450ft/lbs kinetic energy?
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Old May 11, 2005, 02:29 PM   #10
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Chirs in Va:

No, the force of the bullet and the recoil of the gun are the same. Believe it or not, it is true. Newtonian Physics. If the bullet were to remain stationary, as in it were somehow permenantly affixed to an immovable object? What would happen is that the powder charge force, which would be directed in all directions at once (which it does normally, BTW) would essentially be directed at the bullet and at the back of the gun with the same magnitude, as happens normally. The gun would accelerate in the normal fashion, but the bullet wouldn't move (much, actually it does still move some), it's energy would have to be dispersed in some other fashion -- heat, sonics, elasticity, etc. And then the gas pressure would still need relieving. The thing is, the gun isn't designed with all of this in mind -- extra heat, vibration, unrelieved gas pressure, etc. Meaning, in all probability, the gun would kick just as much as before, and then it would blow up.
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Old May 11, 2005, 02:37 PM   #11
InToItTRX
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I once read the only handgun that could do that was the Desert Eagle .50AE, I dont know if it is true or not.
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Old May 11, 2005, 02:38 PM   #12
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"So say the recoil at the Kimber is more like 10ft/lbs, and the bullet has what...450ft/lbs kinetic energy?"

No, the recoil of the Kimber is still 450 ft/lbs. The difference is that the 450 ft/lbs of the bullet is concentrated in a much smaller, lighter, less flexible package than the 450 ft/lbs of the gun and the shooter. The velocity of the bullet ends up being much more than the velocity of the gun/shooter, but when you factor in the masses involved it all comes out equal. Think of it as pushing between a rock and a boulder. You have to push against the boulder just as hard as you push against the rock in order to get the rock to move. You can't selectively push 1 object and make it move, you have to push against something else just as hard.

Newtonian Physics. There ain't no such thing as a free lunch, even when dealing with things like firearms. You don't get more energy out of the front of the gun than out of the back, it just doesn't work that way.
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Old May 11, 2005, 02:44 PM   #13
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How much of the recoil is due to the high speed gases exiting the gun. I ask because isn't that how muzzle breaks work? Don't they direct the high speed gases backwards, so that instead of a certain number of grains (same weight, remember) of gas flying out the front at 5000 ft/sec, it goes to the side, and thus produces less recoil?


Furthermore, technically, to knock someone over, wouldn't you just have to dump enough energy that thier center of gravity got off balance, and they fell over? Think about it this way, if someone catches a soccer ball mid chest (and holds onto it), and is not well balanced, he will probably be knocked over. Wouldn't the same principle apply with a bullet? Of course, that assumes that

1)The bullet dumps all its energy in the person
2) THe bullet dumps all that energy in a short amount of time
2)The person is off balance.

I would say that those qualify as rather big assumptions.
And the important thing isn't that someone gets knocked over, its that they can't get up again. And thats a whole different ball game, and frankly, is much more important then wether someone can get knocked down.

Just some things to think about. And no, i don't put much stock in "knockdown power". This is just my "know nothing" opinion.
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Old May 11, 2005, 02:50 PM   #14
625
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"I once read the only handgun that could do that was the Desert Eagle .50AE, I dont know if it is true or not."

I read that too. I think it was in one of the "Blade" comic book series.
Just messin' with ya. Um, no, the .50AE can do nothing of the sort.
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Old May 11, 2005, 03:06 PM   #15
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Quote:
How much of the recoil is due to the high speed gases exiting the gun. I ask because isn't that how muzzle breaks work? Don't they direct the high speed gases backwards, so that instead of a certain number of grains (same weight, remember) of gas flying out the front at 5000 ft/sec, it goes to the side, and thus produces less recoil?
I don't have the numbers but the gasses have mass too. This is one reason why blackpowder guns have more recoil for the same muzzle velocity with the same weight bullet because you need a couple of times the weight in propellant to produce the same speed and that means more mass to cause the reactionary force. I also read somewhere that the expanding gasses will push against the muzzle, when there is no brake, and add to the recoil from the reactiontary force (terminology?).
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Old May 11, 2005, 03:18 PM   #16
Doug.38PR
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A deputy was knocked down and bruised when a bullet struck his protective vest during Monday’s confrontation. His identity was not immediately released
(Emphasis added)

This was taken from that Compton California shooting report on a CBS website

Note that a policeman was KNOCKED DOWN when a bullet struck him
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Old May 11, 2005, 03:26 PM   #17
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People go down when shot, but that doesn't they were physically knocked down by the force of the bullet... unless they were off balance or no longer physically capable of standing because of damage, it is most likely a psychological reaction to being shot. Just because a reporter likes to use that choice of words doesn't actually make it so.

If you want to physically knock somebody down I would suggest a 40mm launcher with beanbags.
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Old May 11, 2005, 03:31 PM   #18
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Please don't ever take the word of the media like CBS as having any expertese about firearms !!!
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Old May 11, 2005, 03:37 PM   #19
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"If you want to physically knock somebody down I would suggest a 40mm launcher with beanbags."

And then, you have to deal with the recoil of that dude. I've not fired a 40mm with beanbags, but the recoil with grenades is STOUT!
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Old May 11, 2005, 03:40 PM   #20
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people's involuntary reactions to being shot are what cause them to fall. i don't think there's many people who can (knowingly) take a gunshot wound and not jerk or jump away to try to avoid further incoming projectiles. see the math earlier in the thread. i can't think of any "bullet" that would knock somebody down. a big bullet will leave a big hole, that's all. even a hit in the vest where the energy is distributed to be more like a stiff punch to the chest won't have said momentum to knock somebody over. a shotgun might do it, but as you get into rifles that have the kind of recoil that's comparable to a heavy magnum shotgun load, it's going to be impossible not to overpenetrate.
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Old May 11, 2005, 03:49 PM   #21
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"even a hit in the vest where the energy is distributed to be more like a stiff punch to the chest won't have said momentum to knock somebody over."

Correct. That is also the correct answer to those who claim that energy dump on the target is so important in a SD round/bullet. Uh, a hit to the chest to someone wearing a vest results in 100% energy dump on the target. The bullet is stopped cold. And yet, the person is able to walk away, nothing worse than being winded and bruised, or maybe having a cracked rib. Point: Energy dump means exactly squat. Penetration, Tissue Damage and Shot Placement are what counts. No handgun has enough energy alone to do the job.
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Old May 11, 2005, 03:54 PM   #22
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A 40 mm with bean bags dosent have much recoil and its still not going to knock them down
There have been lots of people take numerious hits from 40 bags with little or no noticeable effect
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Old May 11, 2005, 04:01 PM   #23
gb_in_ga
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"A 40 mm with bean bags dosent have much recoil and its still not going to knock them down"

Ah -- learn something new every day -- I did say that I've never actually shot one of those. Well, if it doesn't have the recoil, it isn't going to knock them down. Sounds pretty useless, in other words.
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Old May 11, 2005, 04:17 PM   #24
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What gun do you think can come close to doing this?

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Old May 11, 2005, 04:29 PM   #25
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According to Newton's laws, if firing the weapon didn't take you off your feet, the impact won't take the target off its feet.
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