As mentioned the gauss rifle usually uses magnetic coils to propel rounds. This guns has appeared in several games, most notably Stalker and Fallout. Despite this, a real life counterpart doesn't exist. As of now a "Gauss Rifle or Coilgun" is only created, and used, by hobbyists, it's not manufactured for military or law enforcement agencies. T
The rifle is named after Carl Friedrich Gauss. In video games, it usually appears in the science fiction or post apocalyptic genre. In the latter, it's usually a very rare gun, or a prototype, often it is an extremely powerful weapon.
In Fallout 2 the M72 Gauss Rifle is found near the end of the game, in San Francisco being carried by some guards or the "Shi". The weapon is used by the Enclave as well. It uses the fairly rare 2mm EC ammo.
The Gauss Rifle is one of the most powerful energy weapons in Fallout 3. Along with dealing devastating damage the weapon will frequently knock an opponent over. It functions similarly to a railgun as it does not utilize chemical propellents to fire the round but electromagnetic propulsion instead. The weapon is the spiritual successor to the M72 Gauss Rifle in Fallout 2 and Fallout Tactics: Brotherhood of Steel.
Fallout New Vegas
The "Gauss Rifle tradition" continues in New Vegas as well. It is often carried by Brotherhood of Steel paladins. Like in previous games it utilizes microfusion cells. It is one of the most powerful per shot weapons in the game, although it's DPS (damage per second) is quite low, due to it being a single shot weapons. It uses 5 microfusion cells per shot, after which the player character must reload.
A unique version exists called the YCS/186, it can be obtained from a hostile mercenary east of Brooks Tumbleweed Ranch, unless the Wild Wasteland trait is taken, in which case the player can get the Alien Blaster instead.
The Gauss Rifle appears in all Shadow of Chernobyl, Clear Sky and Call of Pripyat, although obtaining the rifle is difficult as it is very rare as is the ammunition it uses. The player will often find one near the end of the game, and it is the most powerful weapon in all 3 games. As mentioned the weapon is found very late in the game, and the ammo is scarce and very expensive, bringing into question its effectiveness.