How a gun works
A gun normally consists of 4 main parts – the bullet, the gunpowder, a brass casing and a primer that ignites the gunpowder. The brass casing houses the actual bullet. The primer and the gun powder is hold by the brass casing. The firing pin strikes the primer causing a small explosion and lighting off the gun powder. The gunpowder's burning produces a lot of gas which pushes the bullet out of the cartridge, down the barrel of the gun, and out. If you were shot at point-blank range, the bullet would go strait through any of your limbs/organs because of the speed of the bullet.