Railguns use magnetic fields to propel a conductive projectile, like a metal rod, to incredible speeds. Railguns do not rely on propellants or explosives, and instead make use of kinetic energy to destroy their targets. In most games, railguns tend to be some of the last weapons the player gains, and usually come in the form of advanced sniper rifles or instant-kill weapons.
Railguns have been used in gaming for at least a decade, and continue to see constant use, taking on many shapes, including vehicle and artillery mounted versions.
Possibly one of the most popular and easily recognizable versions of the railgun, the version in Quake II fired a depleted uranium slug, producing a spiraling puff of blue smoke along the projectile's trajectory--an effect modeled after the railgun in the movie Eraser. Later versions of the weapon in sequel titles Quake III, Quake 4, and Enemy Territory: Quake Wars also use a similar weapon, but with slight changes the appearance and effects of the weapon.
Appearing as both a handheld rifle fielded by infantry and as a vehicle-mounted heavy weapon, the Crysis railgun is one of the most powerful weapons in the game. Able to shoot down alien hunter robots in two shots, the railgun rules the battlefield and is featured extensively as an American Military armament.
A railgun appears in BF: 2142 as a stationary, anti-vehicle emplacement. The Rorsch Mk-S8 can destroy most vehicles in a few shots.
Lo Wang sports an extremely powerful version of the railgun in Shadow Warrior. Able to penetrate multiple enemies with a single shot, the railgun is often an instant-kill weapon.
Red Faction's rail driver is a late-game weapon that can fire through walls by utilizing a heat-sensing scope.
Metal Gear Solid
In Metal Gear Solid, Metal Gear REX is outfitted with a rail gun mounted as its right "arm" used to fire stealth nukes anywhere on the globe. In Metal Gear Solid 4, Liquid Ocelot steals the gun off of REX and attaches it to his warship Outer Haven, which he plans to fire at a satellite to destroy the AI " JD". Also, in both Metal Gear Solid 2 and 4, characters wield large, handheld railguns; in MGS2, it is unusable, a weapon used by the boss Fortune, while in MGS4, it is acquired by the player after defeating Crying Wolf.
Possible Future Uses
The railgun could be used for long range attacks on bases and also cover fire from over 440miles away check the video how this could be used here