Do you think the Cattle Bolt gun from No Country for Old Men could actually do everything it did?

No

Yes.

Maybe..

Without a doubt. Depending on the PSI that the tank and connections could handle. It would be pretty easy to do. I was bored at work one day and using some spare parts made gun that could shoot stuff really far. That was from the tanks on the soda machines. I mean like I fired nuts and bolts far enough that I don’t know where they landed.I could see them for a while.

I just love the progression of the answers! I don’t know a thing about guns…nothing to add.

not at all….

It’s physics. If that thing were to blow out a lock like that, a recoil of equal force would be returned into the opposite direction. That force is what actually moves the slide in an automatic, and the reason revolvers have so much more recoil.

Same with people in the movies getting hit by a bullet and flying all over the place. Same amount of energy goes both ways, something like that. Basically that means the shooter would fly just as far as the hit body.

@TaoSan; not per se. The same amount of momentum must be transferred to the gun and its operator, because momentum is the product of force and time, the gun feels the same force as the lock, by Newton’s third law, and the force clearly acts on both for the same amount of time. But while the force on the lock acts only over a distance of some six inches or so, when the operator tries to slow down the recoil he can do so over the entire length of his arms; and because the gun is much more massive than the bolt, it will cover this distance considerably slower, as well. So the time over which the force of his arms can act is much greater, and therefore the force he must use is proportionately smaller.

That deals with the question of whether the shooter would have enough strength to handle the gun. As for what happens to his body afterwards: ultimately, as momentum is conserved for a system, he and the gun must collectively have the same momentum as the lock, but momentum is also the product of mass and velocity; as they are much more massive than the lock, they will move backwards much more slowly. Not knowing the specific values in the system, and allowing that considerably more force is needed than that described, given that some momentum is transferred to the door by friction, I cannot say whether it would actually be possible; but its is not a simple open-and-shut case.

However, the whole thing with people flying backwards after getting shot is clearly impossible, because the difference in mass between a bullet and a gun is insignificant compared to the masses of two people, and so each person’s momentum, and therefore velocity if they are of the same weight, should be approximately the same. Of course, the shooter may have braced themselves while shooting, thus transferring momentum to the earth; but if they are simply standing, running or falling as they usually are in movies, they would have to flay backwards just as far as their victims do; and since they don’t, it is clear that the victims ought not to either.

I thought I summed that up with ”…something like that” ;)

Your’re absolutely right though. However, short reminder, he doesn’t actually use a “bolt gun” as muzzle, but merely the hose with a quick release valve, holding it fire extinguisher-style. Thus, not much mass to absorb energy.