ARC-920 railgun

The Asymmetric Recoilless Carbine-920, abbreviated ARC-920 or known simply as the Railgun, is a compact-channel linear accelerator weapon used by the United Nations Space Command. It was designed and manufactured by Acheron Security.

Design details
Like the M99 "Stanchion" Rifle, the ARC-920 uses a series of electromagnets to accelerate its projectiles. The rifle requires a brief charging period before firing high-explosive rounds accelerated to an incredible speed. The explosive yield contained in the round adds to the kinetic force of the impact, making the weapon effective against both infantry and armor.

The weapon lacks zooming capabilities. However, if you zoom in using the suit's default 5x zoom, the weapon can be charged and fired with the zoom only being broken by the shot firing. This can be used to give greater precision to long-range shots.

Gameplay
Compared to the Spartan Laser, the ARC-920's charging time is half the duration and deals less damage to vehicles, but in the campaign and in Spartan Ops, the charging time is extended. This is fixed on multiplayer games. In addition, the travelling time for a fired shot is almost instantaneous. In Spartan Ops the ARC-920 features the additional advantage that - unlike the Spartan Laser, Rocket Launcher and Sniper Rifle - it can pick up additional ammunition from ammo crates, giving they player a potentially unlimited supply of ammunition.

Trivia
In canon, a magnetically accelerated projectile should be moving at a fraction of the speed of light. However, the Railgun's projectiles move at a much slower subsonic speed. This is presumably for gameplay balance.

List of appearances

 * Halo 4