Editing Mark 2555 heavy railgun

{{Status|Canon}}
{{Weapon infobox
|name=Mark 2555/20cm heavy railgun
|image=[[File:HW2 Blitz Colossus.jpg|300px]]
|caption=The Mark 2555 railgun mounted on the left shoulder of a Colossus.
|manufacturer=
|series=
|type=[[Railgun#Heavy railguns|Heavy railgun]]{{Ref/Reuse|Enc22}}
|cost=
|variant=
|service=[[Post-Covenant War conflicts]] {{C|presumably [[2555]]-present}}
|length=
|width=
|height=
|weight=
|ammotype=20cm rounds{{Ref/Reuse|Enc22}}
|capacity=
|feed=
|operation=
|rate=
|velocity=
|optics=
|range=
}}
The '''Mark 2555/20&nbsp;cm heavy railgun (HRG)''' is an electromagnetically-operated heavy artillery piece in the service of the [[United Nations Space Command]].{{Ref/Book|Id=Enc22|Enc22|Page=146}}

==Overview==
===Design details===
The Mark 2555 follows the older [[Mark 2547 heavy railgun|Mark 2547]] model, operating as a heavy [[Railgun (fiction)|railgun]]. The weapon was originally designed to fire from a fixed position, and was intended to be mounted atop static structures and fortifications.{{Ref/Game|HW2|Phoenix Logs|Detail=Colossus}} 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 20&nbsp;cm slug from its rails, and is considered a long-ranged weapon.{{Ref/Reuse|Enc22}}

==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 {{UNSCShip|Spirit of Fire}} in the [[Second Ark Conflict]] in [[2559]]. During the war on the [[Installation 00|Ark]], multiple Colossi sporting Mark 2555 HRGs were used during [[Operation: SPEARBREAKER]].{{Ref/Level|HW2|Not On My Watch}}

==Gallery==
<gallery>
File:HW2-QuadColossus_Concept.png|Earlier concept art for the Colossus, depicting a railgun turret more obviously lineaged from the [[ARC-920 railgun]] in the ''Halo'' FPS games.
File:HW2_-_colossus_art.jpg|Finalised concept art used for the final Colossus vehicle, with a view of the Mark 2555 railgun without its mounting.
</gallery>

==List of appearances==
*''[[Halo Wars 2]]'' {{1st}}
**''[[Halo Wars 2: Operation: SPEARBREAKER]]''

==Sources==
{{Ref/Sources}}

{{UNSC heavy weapons}}
[[Category:Railguns]]
[[Category:Artillery]]
[[Category:UNSC ground weapons]]