Coilguns IRL are similar to railguns in the sense that they're both Magnet-based weapon, but coilguns are smaller, and easier to make, even if they don't scale up well.
Coilguns in cosmoteer could be a high-accuracy weapon the size of the electrobolt that requires both ammo and energy. They have high accuracy, high velocity projectiles that excel at sniping other parts and weapons, but do little damage to armor or shields. High damage and a low firing rate give it less DPS per munitions then other weapons, but the high accuracy means more of the DPS goes where you want it to.
