If I shot a bullet that travels backwards in time, what would it be like?

It would seemingly do nothing. If it hit someone then we would already have heard about it because it was in the past.

You must be careful since it might kill someone important in the past creating a time paradox making the universe to implode.

Some poor sap thats just living his life in the past will get shot in the head. :(

It will be the same as if you shot it normally...painful as fuck!

Well it depends on whether you are referring to bullet that travels back in time, like in reverse motion, or one that travels backwards THROUGH time.

If it's the first, it would pretty boring as it would go back to the gun where it was fired and that's it. If it was the latter it would be more interesting, as people would only see it for an instant as it crossed their present time. If they had the bad luck to be in the wrong place at the wrong time, then they would be hit by the bullet.

I'm not sure what would happen after that, if the bullet would stay in that "time" when it hit the aforementioned victim or if it will keep travelling back in time. Assuming it was able to travel back in time because it somehow was faster than light, then I assume once it hits its target and again assuming it remains within the victim, it will stay there and become a regular bullet.

Well, since time is it's own dimension, your bullet would straight fly backwards into it and eventually hit the DeLorian from back to the future. The Problem with it is, that superman, as he travelled through time would somehow deflect the bullet while he sat in the car so that the flux capacitor gets damaged. Because of the damage, the company of the three people would travell to a T-rex baby that would sit right ontop of the DeLorean. The problem with that is, that the Delorean isn't capable of transporting Superman and the T-rex at the same time, because as everyone knows, they'r arch-enemys. This would make a very strange paradox and because of that paradox, the whole complex of the story would beam into the TARDIS in where DR. Who turned into a giant Moscito who will suck out everything in the Universe for eternity, unless(!) the Daleks who turned into puppys because of a peanut being crushed in the past, which changed the peanutbutter in their pockets( everyone knows puppys spontaniously form when peanutbutter changes) will go back in time and fire a bullet forwards in time at the same time as you fire your bullet backwards, to reverse everything you did.

Basically the bullet alone could not travel which means one thing: that the gun it's fired from is directly and/or connected to the time machine which takes you back in time but leaves the bullet in the present( or future in that case). The bullet would stay the same. Anyway thanks for the chance :)

Like Skyrim, with guns

Firing a bullet requires adding entropy. Entropy increases with time. Firing a bullet backwards in time would require an increase of entropy towards the past while in the forward direction, the bullet would have gone from a disordered state to an ordered state and then entered your gun and assembled into a near perfect state just at the moment you "fired" it. Pulling the trigger would be different as well. The impact of the bullet striking the pin would cause the trigger to move your finger and not the other way around.

Look, you can't fire a bullet backwards through time. There's no way for you to cause it. Causality is a chain that goes forwards. Theoretically, you could say it's possible for events to go in reverse the same way that they can go forwards, but this does not happen in practice. Entropy decreases towards the past and that's just the way the universe works.

Assuming you could break the laws of physics and fire this bullet backwards through time, it would mean that in the past, metal would assemble itself into a the shape of a bullet slug. Another bit of metal would form into the shape of a spent shell casing. Then nearer the present, that slug would spring into motion and fly backwards as it warped itself into a bullet shape, then that bullet would fly towards the barrel of your gun with the exact trajectory needed to enter the gun. The shell casing would fly upwards and fall precisely into the gun at the perfect moment that the shell ejection opened itself and the shell would go into the gun where the bullet would perfectly fit back into it at the exact moment that a burst of kinetic energy and raw materials formed itself into gunpowder.

Now, do you think this astronomically improbable series of events would ever happen?

The gun would jam. The moment you fire it, it travels back in time, but the location stays inside the gun. Therefore, 2 bullets, 1 chamber, slight movement? Gun's jammed.

Well, right now I can recall three main time-travel theories.

One theory was mostly presented by Doctor - in that theory you can only time-travel if you're relatively not moving - flying bullets can't really stop moving. Unfortunately, I can't say for sure if Doctor didn't changed this theory, but in the end this one is probably most popular.
There's also some variant of that theory, known especially thanks to collaborations of Skynet and John Connor - in this case, time traveling is only allowed for skin and whatever is covered by it - making it even more impossible for bullets to time-travel, unless you cover one with skin, but that probably won't work due to temperatures when you fire one.
But there's also theory presented as first (at least to me) by Jean-Claude Van-Damme, where time-machine must move to be able to jump. That means, if time-machine would move fast enough you could shoot in it and bullet would travel back still moving.

The back of the gun would explode.

Then the bullet would continue traveling the wrong direction trough your past.
Fast, very fast. All the good and bad times in your life, a reflection.
Eventually flying slower, until it arrives at the time when you were just a kid in school and had your first fight with the bully.

The bullet would then hit the bully and... woosh... fast forward again. Trough time, faster and faster up until right now. You just unloaded the bullet, and now you think about why you did it in the first place. Why would you want to hurt someone like the bully hurt you as a child?

It would back to place where it was before.

Since the bullet is fired there is no stoping it,even if the bullet goes back in time it goes straight so it has to hit something.

It would go backwards instead of forward causing the gun to pretty much explode in your hand and most likely killing in the process.

Loud.

A dinosaur cries

The bullet would be unstoppable and just go through anything!!!!!!!

Fortix.

You are misunderstanding what time is. You have to understand that time is a fourth dimension and not merely the sequencing of events. Simply put, time is God's way of making existence comprehensible to us, for without it, everything would happen all at once. Put another way, an object or occurrence occupies particular spaces at particular times in accordance with various factors.

Your bullet, therefore, cannot be "shot" backwards in time because the shooting itself designates a particular flow of time (forward, from the time of ignition). And while it is possible to follow the bullet backward in time (toward it's creation as a bullet), you would not be able to perceive that as movement because your own perception is grounded in "forward" time.

TL;DR: The bullet already exists in the past, but the "shooting" cannot.

There is many ways that I can personally see this. By backwards in time, you mean the process of the bullet deconstructing itself into resources that was once used to create the said bullet and powder, then it would probably be a powdery sandy mess just pouring out of the barrel of the gun; assuming by fire you mean using a gun. If the bullet traveled back in time, like as the bullet travels forward, it would go back in time like the world was rewinding to it, then I would say from our perspective it looks like a type of impact was created but no trace of its existence while a bullet drops in mid air to where the gun is fired. UNLESS I am wrong and what it would be like is firing a gun, but instead of losing ammo and creating a bullet hole it would be like you point a gun at a location and the bullet holes that are there disappear and suddenly a bullet in the gun appears- which is possible because some say it is impossible to change the future- that destiny exists. However, the question remains about the bullet hole. The bullet hole is not the bullet, so if the bullet travels back in time, does that include the environment around it, including the damages the bullet left? It is possible that when this bullet travels in time when fired from a gun, in any outsider's perspective, it would be hardly different except there will be no traces of bullets remaining within the point of impact.

em... i like trains

It would go back in time and become a cannonball eventually, then maybe something like a spear, and then probably a plain stick and continue traveling until it struck some microscopic water animal...killing it upon impact and thus killing off all life at that time, and henceforth all life in the present which would kind of be like a game based on the movie, The Room.

The universe would likely cancel your bullet out of existence, and perhaps you.. if your development of it was going to collapse reality as we know it. The Universe usually has a nice orderly way of sorting itself out :D

Hm... ask Gaben. He knows all.