Mark 2547 heavy railgun

The Mark 2547/35 cm heavy railgun (HRG) is a vehicle-mounted railgun in the service of the United Nations Space Command, affectionately referred to by UNSC personnel as a "mini"-Magnetic Accelerator Cannon. The Mark 2547 is most commonly found mounted atop the the M510 Mammoth siegeworks vehicle.

Design details
The Mark 2547 is a large heavy railgun, and presumably a predecessor to the sequentially-numbered Mark 2555 heavy railgun. It fires a 35 cm projectile and is considered "exceptionally powerful" - capable of destroying even Forerunner structures such as particle cannons. It can be used to target both ground and air targets, and can be used in conjunction with a laser designator to coordinate attacks.

Operational history
Given the weapon's designation of Mark 2547, the weapon presumably entered service around the year of 2547. It continued to see service into the post-war era as the primary armament of the M510 Mammoth vehicle, with several in service among the Mammoth fleet of. In July 2557, one such weapon was used by Infinity ground forces during the Battle of Requiem. The artillery was used in conjunction with a H-295 target designator operation by John-117 to eliminate several Z-8060 particle cannons.

List of appearances

 * ''The Commissioning
 * Halo 4
 * Halo 5: Guardians
 * Halo: Tales from Slipspace
 * On the Brink
 * Halo: Official Spartan Field Manual