Mark 2555 heavy railgun

The Mark 2555/20cm heavy railgun (HRG) is an electromagnetically-operated heavy artillery piece in the service of the United Nations Space Command.

Design details
The Mark 2555 follows the older Mark 2547 model, operating as a heavy railgun. The weapon was originally designed to fire from a fixed position, and was intended to be mounted atop static structures and fortifications. However, they have since been installed on the modular hardpoints of the HRUNTING/YGGDRASIL Mark II (J) Colossus walker, with the vehicle's most common configuration mounting a Mark 2555 on the left shoulder, above the M193LP autocannon. In this configuration, the weapon is capable of targeting only ground units.

The Mark 2555 railgun fires a 20cm slug from its rails, and is considered a long-ranged weapon.

Operational history
Based on its model designation, the Mark 2555 presumably entered service in the eponymous year of 2555. It was used by the forces of in the Second Ark Conflict in 2559. During the war on the Ark, multiple Colossi sporting Mark 2555 HRGs were used during Operation: SPEARBREAKER.

List of appearances

 * Halo Wars 2
 * Halo Wars 2: Operation: SPEARBREAKER