Throw a live round in a campfire – what do you think is going to happen? Do you think the bullet will shoot out almost like from a gun? Do you think it is going to explode, throwing shrapnel all over the place? Or maybe nothing’s going to happen and that round will just heat up without significant danger? Here is what is going to happen and why people believe in myths about bullets and campfires.
Ok, so a normal round is made from a case with a bullet at one end, a primer at the other end and some gunpowder in the middle. Once a striker pin of a gun strikes the end of the case, a primer lights up, setting gunpowder on fire. This makes for a lot of expanding gasses that shoot out the bullet, which is then directed by the barrel of the gun. If you throw a live round into fire, nothing is going to ignite the primer – there is no striker in a campfire. However, gunpowder will eventually reach the temperature of ignition and will light up causing those hot expanding gasses to appear.
Now, it is important to note that you should never ever throw any live round in fire or in any kind of extremely hot place. It is a very stupid thing to do, which may cause significant injuries to people surrounding the fire. Don’t be so irresponsible – do not ever throw live rounds anywhere near the fire.
Having said that, most likely nothing significant would happen. Surely, the gunpowder would explode and there would be those expanding gases, but the bullet is highly unlikely to leave the case. This is because those normal cases are rather thin. Expanding gases would escape through a path of least resistance, which would be the wall of the case. In other words, a new hole on the side of the round would appear, but, most likely, the bullet would remain in place.
You can see an experiment with more explanation here:
But why is that? Why exploding gunpowder does not tear a new one on the side of the round when it is fired from a gun? Well, that’s the clue – the gun. The barrel of the gun provides additional support for the walls of the round. When a bullet is fired from a gun, the path of least resistance is actually through the bullet. That is why modern guns are designed with tight tolerances and significant heft to their frames to withstand the pressure exerted to the sides of the cartridge.
But still, you should never do that. Although this is what is most likely to happen, weirder things have happened. It all depends on the case and the round and the fire. Some ammo might have stronger cases or lighter bullets. There is absolutely a chance that a bullet might shoot out (although with not much power) or a piece of a case can injure someone.