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[Rockman]

And it involves guns too!

Okay so we know that each reaction has an equal and opposite reaction, so when a bullet is fired the force required to send it soaring must have an equal and opposite force. Well what happens to that force. I know some of it is in the kickback, but it seems like more force should be expended than just that. Especially with a fifty cal round.

I've actually seen the answer on mythbusters, but I can't recall correctly.

BTW this conversation started because while watching Kindergarten cop today at a friends house I commented on how silly it is in the movies that people go flying when hit by guns, because then that same force should drive the shooter back too. My friend didn't think this was the case, but I'm not entirely sure what the accurate answer is.

[avengingtitan]

Well movies arent supposed to be accurate.

There is a significant kickback on most weapons. The difference is the shooter usually is prepared for it and braces himself/herself for the shot. The body absorbs the kickback, its after you shoot a lot your legs can sometimes get woozy.

[Doc Jon]

I've seen a shotgun knock a kid who was firing it on his ass.

[spidertour02]

Okay so we know that each reaction has an equal and opposite reaction, so when a bullet is fired the force required to send it soaring must have an equal and opposite force.

Not exactly -- if the sum of the forces was zero, the bullet wouldn't accelerate.

But the quick answer is that the reaction would be a combination of kickback and dissipated energy through heat.

[Rockman]

I've seen a shotgun knock a kid who was firing it on his ass.

yeah but I doubt it sent him sailing back five feet in the air.

[Rockman]

Not exactly -- if the sum of the forces was zero, the bullet wouldn't accelerate.

But the quick answer is that the reaction would be a combination of kickback and dissipated energy through heat.

I wish I would have taken a physics class in college, I only know the really rudementary stuff which is sad

But that makes sense I suppose.

[Doc Jon]

yeah but I doubt it sent him sailing back five feet in the air.

That may be a movie effect.

[Rockman]

That may be a movie effect.

oh I know, but you know how when you're barely watching a movie you just grab at something as a conversation starter.

It led to watching a really cool youtube video about the effects of various munitions on a barrel of water. Very cool and someone disturbing once you see the entry hole compared to exit hole.

[avengingtitan]

yeah but I doubt it sent him sailing back five feet in the air.

I watched a guy fly five feet in the air when he fired an elephant rifle. To be fair he wasnt told exactly what it was, just that it was a varmint rifle.

[Rockman]

I watched a guy fly five feet in the air when he fired an elephant rifle. To be fair he wasnt told exactly what it was, just that it was a varmint rifle.

lol

You ever see those pistols that hikers use for grizzly bears? They look like souped up derringers, but their bullets are like two inches long.

[Strict31]

AMS, this is going to depend heavily on the weapon firing the bullet.

Most semi-auto and full-auto weapons depend upon gas blowback to slide the receiver back to load another bullet. That is, the gases expelled from the discharge of the round are funneled back through the weapon to drive the mechanism. This helps to disperse (to a large degree) the recoil of the bullet being fired.

It's also gonna depend on the size of the round being fired. The M-9 Beretta, for example, fires a nine mm round. The design of the weapon, and the lightness of the round allows the gun to fire three rounds before the recoil of the first shot is felt by the shooter. In other words, the mechanism is operating faster than the force from the recoil is transferred back to the user.

But it is generally a myth of Hollywood that bullets cause people to fly back through walls and shit when they get shot. For the most part, people just drop. And if a large round (or number of rounds) hits a person with enough force to physically move them, it's probably going to do some nasty and messy things to the body before that happens. A .50 cal round is more likely to destroy whatever body parts it's hitting before slamming the target through the air.

A friend of mine used the .50 cal Browning M-2 during the first Gulf War. That round hits a target in, say the hand? It tend to blow the guy's entire arm off. And I don't mean it just falls off. I mean that arm is gone.

For a bullet to physically drive a person through the air when it hits, it would have to confer its kinetic energy fairly evenly across the person's entire body.

Which defeats the purpose. Instead, they focus that energy into a very small point of impact, generating an evacuation of soft tissue and a sort of cavitation. You can see this more clearly in the ballistics gel that Mythbusters occasionally uses.

But, when you see guys getting hit while wearing ballistic vests (which do disperse the kinetic force across a large space) you will see guys getting knocked down on their asses. Not so much flying through the air, but still, that's about as close to what you're talking about as reality will get.

So, while that's still a lot of force being transferred, and many guns will still deliver quite a kick back to the shooter, most of the force is dispersed through blowback mechanisms or other forms of recoil compensation, like muzzle breaks or what-have-you.

[achilles]

All of which is correct. Still, I recall shooting my .454 Casull, (Ruger Super Redhawk), for the first time with mild training rounds, and wound up with a nasty gash on my forehead when the recoil drove the barrel back into my face. And it caused every other shooter on the line to look over, and a few to come ask what it was, even the guy shooting the .50BMG.

But really, no gun is going to send the person it hits flying back like in the movies, (Last Man Standing, I'm looking at you), for the reasons Strict mentioned.

[muddyglass]

A friend of mine used the .50 cal Browning M-2 during the first Gulf War. That round hits a target in, say the hand? It tend to blow the guy's entire arm off. And I don't mean it just falls off. I mean that arm is gone.

using it on human beings is overkill. that monster will blow up cars and trees!

[Strict31]

using it on human beings is overkill. that monster will blow up cars and trees!

It's one of the few "small arms" rounds in the world where you could pull the bullet right out of the gun and stab someone to death with it.

[achilles]

using it on human beings is overkill. that monster will blow up cars and trees!

Overkill? What's that?