i see it in movies all the time and wonder "wouldn't the bullet fall down and kill someone

It would depend on the velocity. If the bullet achieved escape velocity, it's in outer space. If not, Earth's gravity pulls it back down.

If the bullet reached escape velocity it would burn up in the atmosphere. :)

Depends on what metal(s) make(s) up the bullet. Look, this whole thing's April 1st silly, but all I'm saying is that the bullet wouldn't necessarily come back to Earth under certain circumstances.

What circumstances would a bullet defy the laws of physics and gravity?

An object needs to achieve a speed of 11.2 km/sec in order to escape the Earth. If a typical bullet reaches that speed shot from a typical gun, and doesn't disintegrate in the atmosphere, then natural laws are defied. I'm talking about more specialized equipment.

It's a common misconception that bullets are capable of remaining airborne after being shot into the air. The closest you will get to that kind of speed, where the bullet would escape the atmosphere and no longer be affected by gravity, is the .900 JDJ round, which is not shoulder fired, therefore you would need a special mount to shoot the gun into the air. The only occasion in which it would be capable of killing someone is if the round was .40 caliber or higher (in pistol terms); a round smaller would probably not have the velocity capable of killing force. Plus, it would have to land in certain areas of the body to prove lethal, so to answer the question and this comment I am replying to, it will not escape Earth's gravitational reach, and it will probably not kill anyone if it comes down and hits them.

If an escape velocity gun existed, I doubt it would be hand held.

True. But IMHO, nothing's impossible. Besides, the inertia of, say a 9mm bullet is easier to overcome than say, a cannonball.

That's actually an issue with shooting in the air. I remember a bullet flew down at a race track while a race was happening and killed one of the audience.

But aren't they supposed to use blanks?

Yes, bullets come down. Gravity. Lol.

It's been tested, check out Mythbusters, they test all sorts of things like this. They've been going for years.

I mis Mythbusters man.