A Medusa Siege Gun of the 143rd Death Korps of Krieg Regiment, 378th Artillery Company, P Battery

The Medusa is an Imperial heavy artillery siege gun used by the siege armies of the Astra Militarum to bombard heavily fortified enemy positions. Evidence exists that the Medusa was originally deployed during the time of the Great Crusade in the late 30th Millennium. At that time, the Medusa was used by the Space Marine Legions as a potent siege weapon.

Besides its field artillery companies, the backbone of any siege regiment of the Imperial Guard are its heavy artillery companies. The heavy artillery pieces used by these companies are the big guns, deployed well back from the front lines to provide a sustained bombardment of the enemy forces during a major set-piece engagement. Imperial heavy artillery includes the Guard's workhorse, the Earthshaker Cannon, and the aging Medusa heavy siege gun. Both types of heavy artillery are capable of firing sustained bombardments, box barrages to isolate a battlefield from enemy reinforcements, harassing fire during an enemy advance, counter-battery fire to suppress enemy artillery and destructive fire at selected enemy units, all spotted for by artillery officers who serve in the dangerous role of forward observers on the front lines.

Siege regiments of the Imperial Guard are supported not only by their own heavy artillery companies but also by the overall army's bombardment corps. These are concentrations of heavy artillery pieces like the Earthshaker and the Medusa that back up the attacking regiments and are used to maintain sustained bombardments before the launch of major offensives against an enemy's entrenched, fortified positions.


Medusa Siege Gun

The Medusa Siege Tank uses the Medusa Siege Gun as its main weapon

The Medusa siege gun fires a heavier shell than the Earthshaker Cannon at a lower velocity over a shorter distance. The heavy shell has excellent destructive capabilities, but the Medusa cannot match the Earthshaker for its longer range and so is less useful for harassing fire and counter-battery fire missions. Instead, it is primarily used to destroy enemy fortifications, such as bunkers, pillboxes, walls and trenches. The Medusa, like the Earthshaker, is too large to be towed by a Centaur field utility vehicle, and the larger Trojan towing vehicle is needed instead. The Trojan can also carry the gun's crew and some of its ammunition as needed. Like the Medusa Siege Tank, the stand-alone Medusa Siege Gun is capable of firing different types of ammunition.

Ammunition Types

  • High Explosive - High Explosive Rounds are the standard shells used by most artillery weapons. These shells are more than capable of destroying infantry units and even vehicles through their sheer explosive force.
  • Siege Shells - Siege Shells are used against enemy structures and fortifications. They are fused to explode after hitting the ground, causing damage to the building's foundation.
  • Bastion Breacher Shells - These shells are fired by the Medusa tank and the stand-alone Medusa Siege Gun. They are fired directly into the enemy walls where they burrow deep and then explode after penetrating, causing the wall to explode outwards and creating a breach for Imperial infantry to enter through.
  • Phosphex Shells - During the Great Crusade and Horus Heresy eras, the ancient Space Marine Legions and Imperial Army forces often employed rare and deadly phosphex weaponry. Phosphex is a rare corrosive toxic and incendiary compound utterly inimical to life, deployed both in the form of large canister bombs and heavy shells. It expands on contact with air into a seething liquid mist which burns with an eerie white-green flame which is attracted to movement. This gelid flame ignites metal and eats relentlessly into living tissue, and cannot be extinguished short of exposure to vacuum. With the destruction of the lone STC by the blasphemous Tech-Priest Veriliad, the Adeptus Mechanicus lost the ability to recreate this deadly substance. It is highly unlikely, that the average Imperial Guard regiment would even have access to such rare and deadly ammunition in the modern 41st Millennium.

Adeptus Mechanicus Technical Specifications

Medusa Siege Gun
Vehicle Name: Medusa Siege Gun Main Armament: Medusa Siege Gun
Forge World of Origin: Lucius Secondary Armament:


Known Patterns: I - III Traverse: 0 degrees
Crew: 6 Gunners Elevation: 0 to 54 degrees
Powerplant: N/A Main Ammunition: N/A
Weight: 12 Tonnes Secondary Ammunition: N/A
Length: 8.2 metres (Carriage Only) Armour:
Width: 3.7 metres
Height: 3.7 metres (Gun at 0 degrees Elevation) Superstructure: N/A
Ground Clearance: 0.7 metres Hull: N/A
Max Speed On-Road: N/A Gun Mantlet: 60 millimetres
Max Speed Off-Road: N/A Vehicle Designation: 0198-561-6730-MG42
Transport Capacity: N/A Firing Ports: N/A
Access Points: N/A Turret:


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