LiquidTension
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Several people upon seeing my suppressed .22 setup say, "you planning to assassinate someone? What's that for?" 
Silly myths you have had to fight with
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I had a teacher in high school who was a veteran of WWII, a marine IIRC, who taught our American history class that the recoil from a 1911 was so ferocious that they were taught in the marines to wedge the elbow of their shooting arm deep into their ribcages and brace the pistol with the off hand on top of the shooting hand's wrist. This placed it very close to the face/head area and when asked about this, he said that it was such a stable position that this never happened. I glanced at his hands and saw no "railroad track" scars, so he must've never actually done this.
I did not bother to tell him that I had not noticed anything too ferocious about the recoil on the 1911 I was shooting quite a bit at that time. I was raised not to openly ridicule my elders. Sad thing was that most of the class bought off on it except for my shooting buddies.
I did not bother to tell him that I had not noticed anything too ferocious about the recoil on the 1911 I was shooting quite a bit at that time. I was raised not to openly ridicule my elders. Sad thing was that most of the class bought off on it except for my shooting buddies.
ScottyT
Member
Been done. Haven't you seen the video of the suicidal guy in a lawn chair sitting in the road. He was holding the gun in one hand between his legs and a SWAT sniper shot it right out of his hand.
Of course unless you are a SWAT sniper yourself or an incredible pistolero, you should probably stick with COM.
I am sure someone can find the video and link it, but I can't get on video sites here at work.
1911Tuner
Moderator Emeritus
Blanks produce a little recoil...but not much. Even though there's not a solid projectile, the burning gasses have mass. That mass is nearly equivalent to the mass of the unburned powder. So, 5 grains of powder is the equivalent of a 5 grain bullet exiting at X velocity. The force required to accelerate that 5 grains of mass at that velocity will likewise be imparted in the opposite direction...and you have an action/reaction event. It's just not much of one.
Blank-firing autopistols operaty because they're straight blowback and because they have a restriction in the barrels to drive up the force required to push the gas volume through the restriction...which also inreaes its velocity...a little like the nozzle on a garden hose increases the water pressure behind the restriction and the exit velocity of a given volume of water.
Justin
Moderator Emeritus
No, it won't.
There are plenty of videos on the web of people testing kevlar vests, and being shot with guns more powerful than .45 ACP, and it doesn't knock them over.
blackcash88
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Justin said:
True. Mythbusters did this and even the mighty .50 BMG didn't so much as knock Buster off the hook he was hanging from. Pretty much, if a bullet is going to "knock someone over", then the shooter of equal weight would be "knocked over" backwards (equal and opposite reaction) as well and we all know that doesn't happen. Heck, he doesn't even have to hit anything since the instant the bullet leaves the barrel, it is no longer has any effect on the shooter.
RustyShackelford
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The Long Kiss Goodnight...
Remember this 1990s stinker where Gina Davis jumps out of a high story window then shoots thick ice with a full auto SMG,!
That was a cool scene but no way in $^&$ could it really work.
RS
PS: I also have serious doubts about Bruce Willis in the first Die Hard, being able to fire several 9mmNATO rounds out of a 92F pistol and break a high-rise office building window.
He may have put a few dents or small holes but no break the entire window! 
It does look cool though...
Rusty
Remember this 1990s stinker where Gina Davis jumps out of a high story window then shoots thick ice with a full auto SMG,
!That was a cool scene but no way in $^&$ could it really work.
RS
PS: I also have serious doubts about Bruce Willis in the first Die Hard, being able to fire several 9mmNATO rounds out of a 92F pistol and break a high-rise office building window.
He may have put a few dents or small holes but no break the entire window! It does look cool though...Rusty
blackcash88
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Or what about when they shoot out the floor around them in the movies like the Matrix?
Jamie C.
Member
Rusty, if it's tempered safety glass, it will pretty much dissolve into a shower of small glass beads or pellets when it's broken. Tempered glass is pre-stressed by heat so that it breaks up into small harmless pieces rather than large shards, even if the spot that's hit is very small. ( You don't want a large piece of anything falling on people's heads several stories below. )
And this is the reason that the window-breakers that police and EMTs use work on the side windows of cars. The breakers are nothing more than spring-loaded punches that drive a sharp point into the glass. They look like a strange ball point pen.
Stress fractures from that one tiny point pretty much carry the whole window out. So it's not impossible that one or two bullets would do the same thing to an office window made of safety glass.
Also, the windows in commercial buildings are no more bullet-proof that than the ones in your house or apartment are. They're just made to break differently for liability reasons.
J.C.
And this is the reason that the window-breakers that police and EMTs use work on the side windows of cars. The breakers are nothing more than spring-loaded punches that drive a sharp point into the glass. They look like a strange ball point pen.
Stress fractures from that one tiny point pretty much carry the whole window out. So it's not impossible that one or two bullets would do the same thing to an office window made of safety glass.
Also, the windows in commercial buildings are no more bullet-proof that than the ones in your house or apartment are. They're just made to break differently for liability reasons.
J.C.
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Deleted member 66305
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ojh said:
As long as the bullet is accelerating down the barrel, it is exerting force on the barrel -- this is Newton's Third Law. Only when the bullet, gas and gun have ceased to be an integral system do the gas and bullet play no further role in recoil.
Sniper X
Member
That a shotgun will knock someone feet back from where they are shot with it.
That a .44 magnum will hit you in the face under recoil or even knock you on your butt if you aren't careful. I actually prooved this one wrong on a hunt where I took a guys Super Blackie and fired all 6 rounds in fairly rapid succession at a target about 10 yards away and all were in the black.
That you can fire a LAW or RPG in a house without doing any damage to whats behind you.
Another movie one, LAWs or RPGs used in war on people as in one person at a time.....
That a .44 magnum will hit you in the face under recoil or even knock you on your butt if you aren't careful. I actually prooved this one wrong on a hunt where I took a guys Super Blackie and fired all 6 rounds in fairly rapid succession at a target about 10 yards away and all were in the black.
That you can fire a LAW or RPG in a house without doing any damage to whats behind you.
Another movie one, LAWs or RPGs used in war on people as in one person at a time.....
You're referring to me
We'll, I have a PhD in physics and I'm teaching pre-service physics teachers in a university, so if I'm wrong, I'm doing enormous harm to the future of my small country The problem is the way that Newton's III Law is traditionally taught in high school physics. By taking forces, and not interactions, as a starting point, and reciting canonical half-truths like 'for every action there is a reaction' it obscures the understanding of what object interacts with what and how, and what is the direction of the interaction. When the spring term ends and I've got more time, I try to put up a small web page and explain these things in detail. Maybe you'll then see that I'm not trying to throw away Newton's mechanics, but use it correctly to explain what's happening when a gun recoils.
Meanwhile, I challenge the unbelievers to explain, how can a speeding bullet inside a gunbarrel push the gun backward, when the only interaction between the bullet and the gun is friction. Or, if you think there's some other interaction between the bullet and the gun, please explain what that interaction is.
ScottyT
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Owned!
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Deleted member 66305
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SpringMom said:
A woman's first gun should be a Cricket rifle, when she's 8.
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ojh said:
I look forward to your web page. I'll be among the first to admit that a seemingly simple problem in physics can become tricky when you really start thinking about it. Ever read in one of Feynman's autobiographies about the discussion of which way a rotating sprinkler will rotate if place in a tank of water, and water is sucked into it, rather than sprayed out?
The bullet, itself, is interacting with the gun only via friction. As the frictional force on the bullet is directed backwards, the force the bullet exerts on the gun is forwards. However, this force is small in comparison with the force the gas exerts on the base of the bullet and the gun, at the other end of the chamber. While the bullet is accelerating down the barrel, the gas interacts with both, and the force exerted on the bullet is the same and opposite to the force exerted on the gun/gas ensemble.
Going back and re-reading what you wrote, perhaps this is precisely what you were saying?
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jackdanson said:
Because bullets start falling at a rate of 9.8 m/s^2 the moment they leave the barrel.
When you throw a baseball, you throw it up a bit, to ensure it connects with the target you were aiming at -- your throw compensates for the fall of the ball.
Similarly, the sights are set so that when you are aiming at a target at the range for which the sights are calibrated, the bullet has an upward component of velocity, so that it ends its flight precisely at the point you intended, and not a few inches lower.
JesseL
Member
shdwfx said:
From what I can tell, in Ohio an 18-20 year old can legally own a pistol, but there's almost no legal way for them to obtain it. They can't buy one, it can't be given to them, and they may not be able to inherit one. However, if they were to construct their own pistol it would be legal.
blackcash88
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JesseL said:
Maybe they're differentiating between simple physical possession and actual ownership. For example, daddy gives his 19 year old son a .22 handgun to go pop some rabbits or something, but he can't keep it forever.
That is right, but it does not not explain the whole thing.
I was mainly trying to explain, what is the interaction that is pushing the gun backwards. The gun and the gas can't be treated as a whole, because the gas is accelerating forward, and the gun is accelerating backwards. Therefore, it must be the interaction between the gas and the gun that's pushing the gun backwards and making it recoil. As said, interaction between the gun and the bullet (friction) is pushing the bullet backwards and the gun forward. But since friction is much weaker than the interactions between gas/bullet and gas/gun, the shootin' iron spits bullets and jumps the way we all know and love
Hmm if I remember this scene, he's actually hanging from a firehose. He jumps off the window and swings away, shooting the glass several times in roughly the same area. Then he kicks through that part of the glass on his return swing. It works in theory, if the glass wasn't outright shattered in the first place (as mentioned above), it would be heavily spiderwebbed (as in the movie) and could potentially break through from a heavy impact.
This can be true, especially if you aren't careful. I have seen weaker people like women hit themselves with handguns. There's even video's of it on youtube. Just did a quick search: http://youtube.com/watch?v=4D2QrT7yYYE though it does appear to be a .50AE, it's still a heavy autoloader to help with the recoil.
I don't think your average guy would have any issue though. Definitely wouldn't knock anyone on their butt unless they have the worst balance imaginable.
Dope
1911Tuner
Moderator Emeritus
Yes it does. Everything else...from friction to recoil spring resistance to the mass of the shooter's arm and the strength of his grip qualifies as outside force. Whatever occurs inside the closed system is understood and accepted to be subject to Newton's laws of motion and conservation of momentum.
The gas is expanding in all directions at once.
The expanding gasses create force. Force is what moves objects. Force forward equals force backward.
For every action, there must be an equal and opposite reaction. Equal being the operative word.
Now then...The physics of the event is off-topic. Let this be the end of it, and return to the matter at hand.
blackcash88
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Try typing in English next time.
-Mgmt.
Whatever...
-Mgmt.
Whatever...
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Deleted member 66305
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1911Tuner said:
Unless you're being very persnickety and accounting for the delta_m = E / c^2 (which is negligible, anyway), the mass is the exactly the same as the unburned powder.
Sorry, I'm another former physicist, and persnickety myself.
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