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Doug.38PR
May 11, 2005, 09:16 AM
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.

XavierBreath
May 11, 2005, 09:19 AM
can .45 caliber knock someone off their feet?
No.

Unless you are shooting at plastic army men.

Ben Swenson
May 11, 2005, 09:29 AM
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?

brickeyee
May 11, 2005, 09:52 AM
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.

gb_in_ga
May 11, 2005, 09:54 AM
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.

SGHOTH
May 11, 2005, 09:59 AM
Only in movies.

However racking the slide on a shotgun will make bad guys stop and surrender. ;)

mete
May 11, 2005, 10:55 AM
'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 !!!

jtkwon
May 11, 2005, 12:42 PM
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.

chris in va
May 11, 2005, 02:09 PM
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? :confused:

gb_in_ga
May 11, 2005, 02:29 PM
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.

InToItTRX
May 11, 2005, 02:37 PM
I once read the only handgun that could do that was the Desert Eagle .50AE, I dont know if it is true or not.

gb_in_ga
May 11, 2005, 02:38 PM
"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.

grey_pilgrim
May 11, 2005, 02:44 PM
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. :cool:
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.

625
May 11, 2005, 02:50 PM
"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. :rolleyes:
Just messin' with ya. Um, no, the .50AE can do nothing of the sort.

novus collectus
May 11, 2005, 03:06 PM
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?).

Doug.38PR
May 11, 2005, 03:18 PM
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

ATW525
May 11, 2005, 03:26 PM
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.

mete
May 11, 2005, 03:31 PM
Please don't ever take the word of the media like CBS as having any expertese about firearms !!! :(

gb_in_ga
May 11, 2005, 03:37 PM
"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!

bclark1
May 11, 2005, 03:40 PM
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.

gb_in_ga
May 11, 2005, 03:49 PM
"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.

CRUSHER
May 11, 2005, 03:54 PM
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

gb_in_ga
May 11, 2005, 04:01 PM
"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.

USP45usp
May 11, 2005, 04:17 PM
What gun do you think can come close to doing this?

Wayne

Yooper
May 11, 2005, 04:29 PM
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.

Gewehr98
May 11, 2005, 04:33 PM
If there's enough energy in a bullet to knock somebody down off of their feet who was downrange from the gun that launched it...

Why is the shooter still on their own two feet?

;)


(Welcome to Hollywood physics, btw!)

brickeyee
May 11, 2005, 04:43 PM
Chris in VA,
you have a major units problem here:

"So say the recoil at the Kimber is more like 10ft/lbs, and the bullet has what...450ft/lbs kinetic energy? "

Momentum is the product of velocity and mass, and has the units of kg x (m/s), or pounds mass x ft/sec.
Energy is mesured in ft x pounds force (often seen as lbf).
The conventional unit system creates the impression that a pound is a unit of mass. It is not. It is a unit of force (correctly labeled lbf). The unit of mass in the conventional systemis the 'slug'. To convert 'pounds' of weight (a force) to units of mass, divide by the acceleration of gravity (32.174 ft/s^2).

"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?"

The fact that the bullet moves has no effect on the recoil of the gun. If the gun weighs 2 pounds, it has a mass of 14,000 grains. With a 230 gr bullet at 900 ft/s the gun has a recoil velocity of 14.8 ft/s (about 10 MPH).

novus collectus
May 11, 2005, 05:30 PM
What gun do you think can come close to doing this?
Panzerfaust :D

gb_in_ga
May 11, 2005, 05:34 PM
"What I'm getting at is I don't believe the forces are equal here."

Believe it or not, they actually are. It is a zero sum game, Newtonian Physics. In cases such as this, the vector sum of all forces involved is zero. It has to be. Yes, there is a difference in mass. Yes, there is a difference in velocity. Yes, there is a difference in surface area. No, there is not a (big) difference in energies. Ok, so there are some added variables that skew the matter, like velocity of the exhaust gasses and such, but in general it pushes just as hard backwards as it does forwards. If anything, those extra variables skew it towards having that much more recoil.

novus collectus
May 11, 2005, 06:02 PM
Ok, so there are some added variables that skew the matter, like velocity of the exhaust gasses and such, but in general it pushes just as hard backwards as it does forwards. If anything, those extra variables skew it towards having that much more recoil.
Just about everything you have said sounds right to me from what I have read. I just wanted to mention the exception I believe exists to your last two sentences....a muzzlebrake. But I guess that is what you meant when you said "in general"?

gb_in_ga
May 11, 2005, 06:12 PM
About the muzzle breaks: Different designs work differently, but in general they move exhaust gasses upwards and backwards towards the shooter. The upwards part of the gas flow exerts a downward force on the gun, overcoming "Muzzle Flip". Backwards exhaust redirect pushes the gun forward, which has the effect of retarding or lessening of the recoil. The gas that exits the muzzle is moving forward, and so pushes the gun backwards, increasing recoil.

Ozzieman
May 11, 2005, 06:24 PM
I have seen it in movies, and movies never lie ;)

novus collectus
May 11, 2005, 06:32 PM
gb_in_ga,
The only thing I have a question about what you have said that I might dissagree with (I might not dissagree if enlightened though) is the bullet staying still idea. This may be hard to imagine from the way I describe it, but lets say you had, instead of the stationary bullet, a tunsten alloy rod attached on one end to the side of a mountain and the other end sticking in the barrel all the way to where a bullet would normally be seated in the cartridge. If you fired the gun, wouldn't all of the force and energy (ignoring energy lost from the backwards force by heat, friction, compression of crystal structures in the metal, barrel expansion, etc.) be directed onto the gun and the shooter holding it and wouldn't the energy that would normally be in the bullets momentum (usage?) be transferred to the backward force of the gun? (I am trying to make the idea of a stationary bullet imagined by using the incompressible, immovable rod in it's place.)

novus collectus
May 11, 2005, 06:34 PM
I have seen it in movies, and movies never lie
Must have been a Michael Moore movie :D

JRLaws
May 11, 2005, 06:42 PM
Goddard amply proves the fallacy of "knock-down power" by calculating the heights (and resultant velocities) from which a one pound weight and a ten pound weight must be dropped to equal the momentum of 9mm and .45ACP projectiles at muzzle velocities, respectively. The results are revealing. In order to equal the impact of a 9mm bullet at its muzzle velocity, a one pound weight must be dropped from a height of 5.96 feet, achieving a velocity of 19.6 fps. To equal the impact of a .45ACP bullet, the one pound weight needs a velocity of 27.1 fps and must be dropped from a height of 11.4 feet. A ten pound weight equals the impact of a 9mm bullet when dropped from a height of 0.72 inches (velocity attained is 1.96 fps), and equals the impact of a .45 when dropped from 1.37 inches (achieving a velocity of 2.71 fps).30

A bullet simply cannot knock a man down. If it had the energy to do so, then equal energy would be applied against the shooter and he too would be knocked down. This is simple physics, and has been known for hundreds of years.31 The amount of energy deposited in the body by a bullet is approximately equivalent to being hit with a baseball.32 Tissue damage is the only physical link to incapacitation within the desired time frame, i.e., instantaneously.
This and other interesting facts @ http://www.firearmstactical.com/hwfe.htm :cool:

wayneinFL
May 11, 2005, 07:16 PM
"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"

A national network says it? It must be true.

Physics-wise a gun is heavier than a bullet, a gun has a larger surface area than the bullet, and the gun travels mroe slowly than a bullet. that's the only differnces between the gun and bullet. Amount of force is the same both ways- energy cannot be created or destroyed.

If anyone doesn't want to believe the physics, hunt with your 45 and see what it does to a man-sized deer or hog.

wayneinFL
May 11, 2005, 07:23 PM
I just remembered where I heard that before- knock a man off his feet. I had an old guy shopping next to me at a gun shop. The taurus dealer was there and I was looking at the 2" 45acp tracker when it came out. The old man turned to me and started talking in a wannabe old west cowboy drawl.

old guy: "That 45'll knock a man off his feet"

me: "really..."

old guy: "Yup."

I just couldn't argue with that.

old guy: "Remember on (some old west show that was on when I was like 3), when Marshal Dillon shot (some other guy)? It took him right off his feet."

me: "That was on t.v."

old guy (unfazed by the sarcasm): "It took six men pulling than actor back with a rope to simulate the effects of that 45 caliber bullet."

me: "on t.v."

old guy: "Six men!"

Old guy puffs his chest, holds head high, hitches his belt like Barney Fife and walks to the next case. Taurus guy, still silent, rolls his eyes.

Lessons learned:

People sitting around watching too much t.v. is NOT a new phenomenon.

A 45 WILL knock a man down, but only if you can tie a rope to him and get six men to stand behind him and pull when you shoot him. Of course, I think this method also works with 9mm, putting that whole 9mm vs. 45 debate to rest...

gb_in_ga
May 11, 2005, 07:25 PM
Novus:

I see your point, but the answer is still, well, no. The point is that the zero sum game still applies. It turns out that the tungsten rod attached to the mountain moves ever so slightly (look at the mass involved!), but it still moves, mostly via compression. That satisfies the zero sum. Now, what happens to that energy afterwards is another zero sum -- it may be that the tungsten rod is accelerated by crystal expansion/contraction -- think "elasticity". The tungsten rod is pushed by the mountain back towards the gun, and equally pushes the mountain. The energy transfer will be nowhere near perfect, there will be much in the way of heat loss as well as loss through vibration, and lost through crystaline stress fractures. But while all this is going on, the gas hasn't had opportunity to escape, and it's gotta go somewhere. It can't go forward, the titanium rod is blocking it, it can't go to the sides due to the barrel. The gun is still locked up, so it can't go backwards. The gun isn't designed to hold this pressure indefinately. Ka-Boom. Just like trying to shoot a gun with a barrel obstruction, because that's exactly what is happening.

The recoil will be the same whether it is a bullet travelling at bullet type velocities, or if it is a mountain being shifted or compressed by a miniscule amount. The zero sum game still applies. In the one case you have little mass and high velocity, in the other case you have humongous mass and miniscule velocity. Same principle applies.

ISP2605
May 11, 2005, 07:51 PM
"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"

Oct 30, 1997 we had been 39 days on a stand off with a barricaded woman armed with a 12 ga shotgun loaded with Federal sabot slugs. When she came out she was hit repeatedly 3 or 4 times in the upper torso with a SAGE 40mm firing rubber bullets. (attached is a pic of one of the recovered rounds.) These things are faster than a well pitched, major league fast ball. Somewhere around 125 mph. She never went down. She was wearing insulated coveralls at the time and just received some bruises. On Sept 26, 1997 we had hit her with several 12 ga bean bags and never phased her.

Dwight55
May 11, 2005, 09:04 PM
Well, guys, I'm sorry, . . . but Newton, and all the rest can go be hanged.

A 40 mm grenade fired from either a "thump gun" or slung under the M-16 will not only knock the recipient off his/her feet with a good COM shot, . . . but it will also relieve them of about 1/3 to 1/2 of their body weight when the round goes off.

Even if the round doesn't detonate: they still go down, . . . and all your fancy theories ain't worth spit. Ask any grunt from 'Nam, . . . that carried a thumper, . . . man mountain Dean himself goes down when that 40mm contacts his sternum, . . . or worse, . . . his flack jacket.

For the record: that "down" is also part of "down and out" for the final count.

May God bless,
Dwight

captbruubaker
May 11, 2005, 09:27 PM
Actually if you watch Last Man Standing with Bruce Willis you will find that it is absolutely true. Because it was Bruce Willis it must be true!!!!!!

Brit
May 11, 2005, 09:37 PM
A 155mm howitzer will do it!! Well actually it converts the body into very small particles! But you get the message.

A school trustee, who stole money, committed suicide on TV a few years ago, stuck a big revolver barrel in his mouth, fired the shot, using a good VCR unit, I was unable to catch movement, one frame there, next frame, gone.

Instant, gravity collapse, no stagger, no step, no nothing, collapse, that is knockdown power, clean off the brain stem whilst standing.
Same as dropping a 200 lb bag of flour.

JohnKSa
May 11, 2005, 09:42 PM
They tested this on Mythbusters.

They hung a man sized pig from a toggle that could easily be dislodged by a light push.

Then they shot it with various firearms. 9mms, .45, various submachine guns, rifles, etc. At one point three of them were shooting it with submachine guns simultaneously.

The only thing that dislodged it from the toggle was a 12ga shotgun. Even then, the slow mo didn't show it getting knocked back, it just got bumped enough for it to pretty much fall straight down.

They decided that too much energy was getting wasted by bullets going stright through the pig so they put a bullet proof vest on it and repeated the test.

Same results. Only the 12 ga dislodged it and it fell pretty much straight down--no significant movement backwards.

Amazing that experiments bear out what the mathematics and science predict, eh? ;)

JRLaws
May 11, 2005, 10:33 PM
I remember seeing an old video where a guy with a bullet-proof vest allows himself to be shot.

He is standing on one leg and is shot with a .308 rifle from a few feet away.:eek: It did not knock him down! I don't think a .45 is going to pull it off if a .308 don't have the juice. The video was Deadly Weapons: Firearms & Firepower, they used to have it playing, on a loop, at a gun store here years ago. :cool:

gb_in_ga
May 11, 2005, 10:41 PM
Dwight55:

No, actually that's in line with what I've experienced. After all, I actually have shot M203 with grenade rounds, I know what the recoil is like from them. So, yes, I can well believe that there is actually enough KE in a 40mm grenade to knock somebody down. Of course, if the grenade detonates as designed that's all she wrote dear John...


JohnKSa:

"Amazing that experiments bear out what the mathematics and science predict, eh? "

After all, that's why they call them laws. Not only that, these are really straightforward ones.

brickeyee
May 12, 2005, 10:51 AM
“ No, there is not a (big) difference in energies.”


“…bullet simply cannot knock a man down. If it had the energy to do so, then equal energy would be applied against the shooter and he too would be knocked down.”

“energy cannot be created or destroyed.”

Momentum is NOT energy.
Energy is MV^2/2, and is measured in lbf*ft.
Momentum M * V and is measured in lbm * ft/sec
They are not interchangeable in calculations.

The ‘tungsten rod in the barrel’ is a poor example, since you are now involving energy, and not just momentum.
When an engineer analyses a problem involving forces a sketch called a ‘free body diagram’ is used to account for all the forces in a simple way. Think of the gun hanging from a thread and fired. Bullet moves one way, gun moves the other, momentum (NOT energy) must be conserved. If the gun weighs 60 times more than the bullet, the gun will have 1/60th of the bullets velocity.
This reminds me of the drawing showing a pair of mule teams pulling opposite directions on a pair of jeans. The pants see the exact same load as if one pair pulled and the other was attached to the mountain. Mule team pulls 1000 lbf North, mountain must be providing 1000 lbf South or the pants would be moving.

A 40mm will only knock someone over from surprise and not being set up to absorb the blow like the shooter was.
I fired a .375 H&H at a deer that ran across a private range where I was checking the rifle. I had already fired 3 shots with the accompanying recoil with out incident. A followed the deer and fired with the rifle 90 degrees to the line between my feet. And promptly was sitting on my but. No way to absorb the recoil.

FirstFreedom
May 12, 2005, 10:59 AM
Nope.

In fact, I was disappointed after just having watched "Open Range" finally, which is overall a good movie - but there were two hokie occasions in scenes when Duvall's shotgun blew someone up off their feet and through the air 6 or 8 feet. A shotgun can't do that - not even close, and a handgun certainly can't.

TheeBadOne
May 12, 2005, 11:08 AM
http://st2.wz.cz/historie/guns/m203.jpg
http://www.globalsecurity.org/military/library/policy/army/fm/21-75/FigG-5.gif
http://www.eskimo.com/~toates/malick/trl/explosion.jpg

About the only shoulder fired weapon I can think of that can "knock someone off their feet"

novus collectus
May 12, 2005, 11:22 AM
About the only shoulder fired weapon I can think of that can "knock someone off their feet"
What about: bazooka, panzerfaust, CHICOM type 36 57 mm recoiless rifle fired from the shoulder(and other recoilless rifles), and the TOW missile, etc. :D

918sgt
May 12, 2005, 11:25 AM
If you want to knock someone off their feet with a .45, hold it by the barrel and hit them with the butt. Hard. You watch too much TV.

ATW525
May 12, 2005, 11:31 AM
I like how he throws in a pic of a hollywood explosion from a WWII movie after a picture of the M203 and a 40mm round... yeah... a 40mm will almost make an explosion like that... lol :p

novus collectus
May 12, 2005, 11:33 AM
If you want to knock someone off their feet with a .45, hold it by the barrel and hit them with the butt. Hard.
Just made me think. A .45 will knock someone off their feet......if it is strapped to the front of a car that hit them at 20 mph.

It will knock them over......if they are one of those Chinese gymnasts who balance on one foot standing on a knife blade while juggling four bowling balls.


It will knock them of their feet......... if they are a 40 pound midget standing in the microgavity of the moon. :D

Glenn E. Meyer
May 12, 2005, 03:26 PM
I've seen tapes of guys hit with a paintball who fall straight down. It's psychological.

As far as the energy impulse of recoil. Years ago, I did something stupid. A friend had a Winchester 1300 with the pistol grip only. We fired it from our waist and then I, as a mental giant, decided to bring it to eye level to aim it. Firing regular buckshot. Well, I ate the gun. But I didn't fall down. I stood there, put the gun down and just cursed myself out.

I also know several other (including a well known national trainer) who have eaten the 12 gauge the same way. So if the recoil whack of a 12 gauge, equivalent, to the energy of the round, won't knock you over, I doubt a pistol will.

shield20
May 12, 2005, 03:47 PM
Ha - I remember duck hunting from a canoe, tracking some Woodies around until I couldn't turn anymore and ended up holding the shotgun like a pistol just with my hands - recoil pad in front of my mouth - OUCH! fat lip (and I missed too - just to make it worse!).


When talking about (pistol) recoil, don't forget the mass of the slide, the barrel, and the recoil spring. If I remember correctly, a recoiless pistol can be created using a heavy enough spring, it just that it couldn't be operated by hand.

Bullrock
May 12, 2005, 06:01 PM
can .45 caliber knocksomeone off their feet?

Not if you miss!!! ;)

LAK
May 13, 2005, 05:02 AM
brickeyeeAny firearm with a bullet capable of knocking someone off their feet would have the same effect on the shooter.

Not only that, it would require a bullet that did not expend it's energy deforming, and a human target that offered sufficient surface physical resistance. Bullets tend to want to pass through people - not "knock them down".

In essence, trying to "knock someone down" with a bullet is like trying to do the same with the sharp end of a spear.

Ben Swenson
May 13, 2005, 11:15 AM
When talking about (pistol) recoil, don't forget the mass of the slide, the barrel, and the recoil spring. If I remember correctly, a recoiless pistol can be created using a heavy enough spring, it just that it couldn't be operated by hand.
I don't think so.

CastleBravo
May 13, 2005, 01:32 PM
It is amazing to read posts by alleged grown-ups that are basically appeals to magic. No wonder so many jobs are going overseas, people here can't comprehend Junior High science class stuff that was figured out by Newton over 300 years ago. Maybe they can out-source gun forums to India, too? :D :D :D

xXStarScreamXx
May 13, 2005, 01:47 PM
I know, i have to teach older guys at gun stores this all the time when they start up on their 45 banter.

brickeyee
May 13, 2005, 02:36 PM
"When talking about (pistol) recoil, don't forget the mass of the slide, the barrel, and the recoil spring. If I remember correctly, a recoiless pistol can be created using a heavy enough spring, it just that it couldn't be operated by hand."

Life does not exactly work this way.
There are two things to consider. Momentum and energy.
Momentum determines the velocity the gun recoils with.
Energy is the KE the gun moving with the recoil velocity posses. The energy can be dissipated over a short distance (requires a lot of force applied quickly) or over a longer distance (requires less force applied for longer). A large mass is required to act against for a gun to be made ‘recoilless’. Something has to hold the non-recoiling portion in position against the springs used to store and release the recoil energy.
Artillery anchors to the earth, stores the energy in springs and hydraulics, and then returns to battery. The actual energy is dissipated as heat in the springs and hydraulic fluid. The advantage is that aiming remains consistent from shot to shot since the base did not move (much, the earth still compresses slowly but surely).
Keep in mind the old demonstration of momentum. A weight is hung from a string, and then another string is attached to the weight. Yanking quickly on the bottom string will break it even though the two sections of string have the same strength. A slow pull might break either one. The momentum of the weight reduces the actual force seen by the upper string. The same type of thing must be in place to allow fro transfer of the recoil KE to the storage mechanism.

CastleBravo,
You have no idea of how bad it is sometimes. I have a little office toy on my desk that rocks a wire framework back and forth. I have lost count of the engineers who think it does not need a battery (perpetual motion has been achieved!).
Engineers using the weight of an object in KE equations (lbf is weight, lbm is slugs), let alone th confusion over when to use Newtons and when to use kilograms in calculations.
Or the new engineer that used narrow traces for high current and used inadequate clearances between high voltage traces. He had no real concept of what these things mean.

Para Bellum
May 15, 2005, 02:59 PM
Nope.

How could it, it doesn't knock the shooter off his feet or dislocate his arm, does it?

Vitali Klitschko would knock you out of your socks. Mike Tyson also would. But no handgun can do that.

jtkwon
May 16, 2005, 10:51 AM
Reminds me of the joke by Ron White. If you just slow the bullet down to 55 mph, put headlights on it, and a horn that's blowing, deer (and I suppose people) will jump right in front of the bullet.

Para Bellum
May 16, 2005, 01:23 PM
Reminds me of the joke by Ron White. If you just slow the bullet down to 55 mph, put headlights on it, and a horn that's blowing, deer (and I suppose people) will jump right in front of the bullet.
:) Man, you made me laugh my socks off! :) ;)

Doug.38PR
May 16, 2005, 05:49 PM
Okay, everyone has fully convinced me that .45 cannot knock a man down.

Let me ask this then: Where does the idea that the .45 has more stopping power than the 9mm or .38 or the .357 has more stopping power than the .38 come from? What exactly is stopping power? I though it was the ability to knock someone back.

While we are on the subject, why did police departments a few years ago decide to start switching from the 9mm to the .40 caliber handguns? They say "The .40 has more 'stopping' power." but what exactly does that mean? I've heard it said on the history channel that they switched to .40 because of the LA shooting about 10 years ago where those two thugs with body armor from head to toe went down the street shooting it out with police who were armed with .38 special and .9mm handguns that could not penetrate the body armor. So they switched to .40 caliber. But that's nonsense because a .40 caliber bullet won't penetrate body armor either just because body armor is what it is. So why the switch?

Full Metal Jacket
May 16, 2005, 06:05 PM
Good question- they switched because getting hit with a 115 grain 9mm wearing body armor hurts, but a heavy bullet like a 230 grain .45acp or a 180 grain .40 SW will feel like getting hit with a sledgehammer...most people wearing body armor won't be able to stand very long with a barrage of 180-230 grain slugs being thrown at em. Don't forget, handgun bullets dont penetrate vests or knock people of their feet, but they can and will break bones and bruise horribly, and the perp wont be able to tolerate it eventually.

PinnedAndRecessed
May 16, 2005, 06:16 PM
or automatically throw people through plate glass windows

You mean that scene in "Last Man Standing" where Bruce Where-has-my-career-gone Willis isn't true? Shocked! I tell ya, shocked!

Doug.38PR
May 16, 2005, 09:28 PM
Good question- they switched because getting hit with a 115 grain 9mm wearing body armor hurts, but a heavy bullet like a 230 grain .45acp or a 180 grain .40 SW will feel like getting hit with a sledgehammer...most people wearing body armor won't be able to stand very long with a barrage of 180-230 grain slugs being thrown at em. Don't forget, handgun bullets dont penetrate vests or knock people of their feet, but they can and will break bones and bruise horribly, and the perp wont be able to tolerate it eventually.

Ahhh. So I guess it is more accurate to say that a .45 caliber CAN knock someone back or down (or any bullet depending on the weight and endurance of the shootee) not because of the bullet itself but because of the damage it does to the person. In other words, if I walk up to someone and slug them across the face or in the gut, my fist isn't what knocks them down but the damage and pain from the blow that knocks the energy out of them and damages their nerves.

Full Metal Jacket
May 16, 2005, 09:36 PM
Ahhh. So I guess it is more accurate to say that a .45 caliber CAN knock someone back or down (or any bullet depending on the weight and endurance of the shootee) not because of the bullet itself but because of the damage it does to the person. In other words, if I walk up to someone and slug them across the face or in the gut, my fist isn't what knocks them down but the damage and pain from the blow that knocks the energy out of them and damages their nerves.

essentially, yes. The bullet itself will not knock someone off of their feet, but broken bones and intense pain sure will get them on the ground pretty quickly.

novus collectus
May 16, 2005, 09:36 PM
Ahhh. So I guess it is more accurate to say that a .45 caliber CAN knock someone back or down (or any bullet depending on the weight and endurance of the shootee) not because of the bullet itself but because of the damage it does to the person. In other words, if I walk up to someone and slug them across the face or in the gut, my fist isn't what knocks them down but the damage and pain from the blow that knocks the energy out of them and damages their nerves.
By George, I think he's got it!! :D

JohnKSa
May 16, 2005, 10:18 PM
It's a little different, but that's much closer. A blow from a fist will actually push a person back much more strongly than a bullet strike will.

In the test that they did on Mythbusters, it was easy to dislodge the 200lb pig carcass with a gentle push. But even machinegunning with three subguns simultaneously didn't impart enough of a push backwards to knock it off the toggle it was hanging from. There is almost NO push applied by the impact of a bullet.

444
May 16, 2005, 11:54 PM
I didn't read the whole thread, so I hope I am not wasting space here.
I have worked as a professional paramedic for over 20 years and have seen quite a few gunshot wounds/victims close up and personal. Most gun owners would be VERY let down when they see the wounds caused by handgun cartridges.
The first shooting I ever went on was done with .45 ACP hardball. A guy asked a girl out, went to her house to pick her up, and her ex-boyfriend shot him through the thigh with a .45.
The guy didn't even care about the wound. He was far more upset about the fact that this other guy couldn't let go of the relationship with this woman. The guy had a through and through wound with no obvious external bleeding. He refused treatment and transport.

PythonGuy
May 18, 2005, 07:22 AM
Ironically, I was watching the "History channel" last night as they had a show on about gunfighters of the old west, and their handguns. One of the show's "experts" stated that a .45 shot from one of the old Colt revolvers was like being hit with a 19 pound sledge hammer and would knock a person flying. How can a so called "expert" perpetuate that myth?, on the History channel no less, when most shooters know its a fallacy? Other then that the show, about gunfighters was excellent, as was the show "Wild West Tech" that followed it. Being we live in the 21st century, we can't have gunfights of course, but even back then most of the fighting stories were exagerrated, not that that should surprise anyone. ;)

brickeyee
May 18, 2005, 08:47 AM
"...we can't carry..."

Maybe in New York, but 34+ other states allow concealed carry.
I hope you feel safer with everyone disarmed (except the BGs who carry anyway)...

PythonGuy
May 18, 2005, 09:43 AM
My point was we can't have gun fights, not about carrying, although we can't carry in NY. Your comment about "I hope you feel safer with everyone disarmed (except the BGs who carry anyway)..." Where did you get that from, I didn't express any opinion on carrying? Talk about selective picking of words, the post was about the myth of bullet knockdown and the History channel. By the way, I'm not anti-carry, I'm anti-being-stupid while carrying. :D

JohnKSa
May 18, 2005, 10:41 AM
PythonGuy,

One of the most distressing things about firearms is that it is one of the few fields where the "experts" spread misinformation.

I just read an article yesterday in which the supposed "expert" made a comment about the .45 Peacemaker being able to knock a person down, or something to that effect.

The sad thing is that THIS particular myth is relatively easy to disprove. The science is quite straightforward, and it can be tested without too much trouble. There are others that are much more difficult to disprove but that are just as false.

3 weelin geezer
May 18, 2005, 11:09 AM
I bet you Mr. Jim Beam could knock you back and he doesn't have to use a handgun!

PythonGuy
May 18, 2005, 11:13 AM
JohnKSa,

I agree, the old saw about "believe half of what you see and none of what you hear" still has a lot of truth to it. By the way, the "expert" on History channel was talking about the Colt Peacemaker too, I wonder if its the same guy you read the quote from?

JohnKSa
May 18, 2005, 11:53 AM
Probably not, it's been repeated and written by so many people, so many times, that it's "common knowledge". False knowledge, but common, nonetheless.

novus collectus
May 18, 2005, 12:00 PM
I bet you Mr. Jim Beam could knock you back and he doesn't have to use a handgun!
Isn't it the other way around? I know I can knock back some Jim Beam :D

Glenn E. Meyer
May 18, 2005, 12:34 PM
Hey, watching the History Channel last night about Gunslingers and some cowboy action guy/ actor said the 45 Peacemake would knock you down!

It has to be true - as it is on TV!

JN01
May 18, 2005, 06:17 PM
Of course a tiny bullet is incapable of physically moving a 200 lb pile of meat, but when it strikes a living person I would think it could cause trauma to various nerves/organs which could cause a involuntary or voluntary jerk, loss of balance, etc. The film of the JFK assassination shows him violently jerking backward after one of the shots, it wasn't from the physical force of the bullet, but his body's response to it.

brickeyee
May 19, 2005, 07:09 AM
A head is a small part of the body’s mass. Shoot a 1/2 gallon milk jug with a high powered rifle and watch all the movement. This moves from a strict momentum problem back into a problem involving energy being transferred from the bullet to the water. Brain tissue behaves very similarly to water when struck by bullets..

Doug.38PR
May 19, 2005, 10:06 AM
A head is a small part of the body’s mass. Shoot a 1/2 gallon milk jug with a high powered rifle and watch all the movement. This moves from a strict momentum problem back into a problem involving energy being transferred from the bullet to the water. Brain tissue behaves very similarly to water when struck by bullets..

That's excessive force!!! How dare you suggest we treat a valueable "member of the community" in that way?!!! ;)


I was told in CHL class that courts don't usually like head shots. They feel it's excessive force :rolleyes:

629 shooter
May 19, 2005, 11:07 AM
Anyone who still believes that a handgun bullet is capapble of knocking down a man just by the force of the bullet impact can shoot something much lighter than a man and see what takes place. Shoot something like a section of a log -large enough for the bullet not to pass through so all the energy is contained. Does not have to be that large or heavy to prevent total bullet penetration from most convetional handguns. Set it up on a table or any surface where the entire base can rest flat. Shoot it and see how far the log moves. If a 45 or any other handgun can truly topple over a man just by the force of the bullet strike - the small log should be thrown quite some distance.

novus collectus
May 19, 2005, 11:14 AM
bullet is capapble of knocking down a man just by the force of the bullet impact can shoot something much lighter than a man and see what takes place.
Tried that with a 12 gauge shotguns slug on a squirell. Couldn't judge if it moved back.....it dissapeared. (just kidding. I never shot a pesky rat like squirell like that....yet)

guntotin_fool
May 19, 2005, 12:26 PM
if you go back to the original post and the question of why the army from a 38 to a 45, you have to look at the original situation.

The US Military Had just faced the 7X57 mausers of the spanish in the War with Spain in both cuba and in the philipines, realizing the superiority of the new rifles, work was to proceed on modernising the weapons of the US. The Krag Rifle was adopted and the .38 Colt was introduced, replacing the SAA colt and the other various 45 cal revolvers. As soon as the spanish had been forced out of the Philipines, a war of insurgency broke out among the philipine people against the US in there attempts to earn independence and self autonomy. In facing the philipino tribesmen, the US military were often facing an opponent who was drugged up, psyched up and in many cases in a nearly crazed state who would attack and fight until he was fully broken down, The Army discovered that the 38 colt did not have enough punch to stop the fight quickly enough. The M1889/1995 revolvers were not known as reliable guns to begin with, and firing a 148 grain LRN at about 750FPS It was not a reliable fight stopper. There were troops in the Philipines still had the Colt SAA as the issued sidearm and these units found that one 250 LRN at 875 to 900 FPS was a huge improvement over a a couple of 148's at 750. With this improvement came confidence in the rounds ability to stop a charging Moro, and with the confidence came more care in aiming and thus even higher success. So a call was made to the army HG for more .45's which were called "man stoppers". As many of the Colt SAA's in Gov't stocks were older and needed to be retired, a call went out for a new pistol to fire a .45 cal 230 to 250 grain slug at or about 835 FPS. JMB took up the challenge and modified a model 1900 auto pistol to hold a new round developed by himself and winchester. Called the Model 1905, the new autoloader and round were not accepted and further testing and competition between UMC and winchester finally ended up with the round and the pistol we know as the 45 ACP and the 1911 Colt pistol. if you wan tot do more look here or google the moro war.

http://www.sightm1911.com/lib/history/background.htm