Coilguns(Pulse Accelerators), like railguns(Linear Accelerators), use intense electromagnetic fields to propel objects at incredible velocities unreachable with modern gas driven weaponry (given enough stored energy of course). A coil gun is known as a reluctance coil gun. The coil uses its electromagnetic field to pull a ferromagnetic(magnetically affected) projectile, in this case a shaped steel round, toward its center. Ideally the current supporting the electromagnetic field will turn off when the projectile is in the center allowing the projectile to continue traveling down the barrel, out the gun, and to the target. Use a coil and a few batteries to understand the properties of this system better. Many coilguns incorporate multiple stages at lower energy levels as efficiency tends to die off as more Stored Energy is used for a single coil design.
While coilguns don't have any industrial application at present, there have been suggestions that these systems could be used to launch payloads into orbit. This is an attractive proposition but there are numerous technical challenges which need to be resolved before it could be considered a feasible project. A more realistic application may be launch boosting where a vehicle is given an initial speed from a long coilgun accelerator. After leaving the coilgun the vehicle would fire its rockets to achieve orbit. Launch boosting could result in significant savings in fuel costs. From a military point of view coilgun technology may have a place in future combat vehicles where, for example, it could form part of a so-called 'active electromagnetic armour' system. Hyper-velocity launching still remains the domain of the railgun, where there is great deal of ongoing research. It may surprise you to learn that the coilgun is nothing new. A pioneer of this particular type electromagnetic accelerator was the Norwegian scientist Kristian Olaf Birkeland.