The Demolisher Cannon is a short-range, large-bore ballistic cannon utilised throughout the Imperium's military forces on some of their most powerful armoured vehicles. Mounted on the Leman Russ Demolisher, Thunderer Siege Tank, and the Space Marine Vindicator, the Demolisher Cannon is a weapon designed to get up close and personal before it is fired. The Demolisher Cannon is the weapon of choice when faced with dug-in enemy infantry in a dense environment such as urban warfare or the siege of a fortified enemy stronghold. The terrific blast unleashed by the detonation of the huge Demolisher shells is often sufficient to bring down buildings in which the enemy take cover, crushing them beneath tons of fallen masonry. It is amongst the strongest weapons fielded by the Imperial Guard at the regimental level and is highly effective when utilised for smashing bunkers, siege warfare and urban bombardment. The sheer damage this weapon is capable of causing is enough reason to risk firing at close-range at an enemy position. This has led to improved armour on Imperial armoured vehicles to increase its survivability on the battlefield when facing a Demolisher Cannon.
The Demolisher Cannon's ammunition is a large calibre, rocket-assisted siege shell larger than that used in the Battle Cannon, composed of an armour-piercing tip, heavy shell casing and large explosive charge. Each shell's rocket engine, fuelled by a solid propellant, is shaped to control time and rate of burn for maximum accuracy. In order to avoid the build-up of rocket back-blast, this gas is vented when the cannon is fired to prevent the barrel from deforming or bursting from the over-pressure. Once fired, the shell is designed to explode micro-seconds after penetration, achieving maximum damage to the target structure and its occupants. The Demolisher Cannon is most often used in a bunker-buster role, by driving up close to enemy fortifications and firing into them at very short range, and allowing allied forces to assault through the breach. They are also used in urban areas, where they are aimed at the base of an enemy-held building and fired, causing the building to collapse.
The Demolisher Cannon used by Vindicators fires a special siege shell, consisting of an armour-piercing tip, heavier shell casing and a massive explosive charge micro-fused to allow penetration of a building or bunker before detonating. The sheer size and mass of the Vindicator's Demolisher shell, however, reduces its stowage capacity and accuracy when fired over long ranges, even with fin stabilisation and booster burns. As such it is also limited to being used for destroying enemy fortifications and fighting in close-quarters combat such as that which characterises jungle warfare.
- Codex: Imperial Guard (5th Edition), pp. 49, 80
- Codex: Imperial Guard (3rd Edition, 2nd Codex)
- Codex: Imperial Guard (2nd Edition), pg. 23
- Codex: Space Marines (6th Edition), pg. 121
- Codex: Space Marines (5th Edition)
- Codex: Space Marines (3rd Edition)
- Imperial Armour - Apocalypse, "Demolisher Line Breaker Squadrons"
- Imperial Armour Volume One - Imperial Guard & Imperial Navy
- Imperial Armour Volume Two - Space Marines and Forces of the Inquisition, pp. 68, 251
- Inferno! Magazine 3, pg. 37