The Mega Battle Cannon, also called the Baneblade Cannon, is a larger, 10-metre-long version of the standard Imperial Battle Cannon and fires rocket-propelled ammunition. It is the primary armament of the Baneblade Super Heavy Tank, the most commonly deployed super-heavy tank of the Astra Militarum.
The Baneblade Cannon is possessed of great range, able to strike targets many kilometres away. Each of its shells is a metre in length and is outfitted with rear-mounted stabilization fins and a small amount of solid rocket propellant in multiple stages precisely calibrated to allow the shell to cross a given range in a precise amount of time. Each shell leaves the cannon's barrel under the force of the initial explosion, but once in flight, the rocket stages ignite in turn, with each booster falling away as the next ignites, carrying the shell onto its target with a speed and range that cannot be achieved using a single, explosive charge alone.
Though the rocket propellant allows the Baneblade Cannon's shells to be fired over a great distance with an unusual amount of accuracy, it can also increase the chance of grave damage to the cannon if there is a build-up of explosive gasses given off from the propellant within the weapon's barrel. To prevent this, the Baneblade Cannon possesses a double-sleeved barrel studded by gas venting ports around the muzzle to allow the harmful exhaust to escape with each shot.
- Baneblade (Novel) by Guy Haley, pp. 10, 125
- Imperial Armour Volume One - Imperial Guard and Imperial Navy, pp. 79-81, 204
- Warhammer 40,000: Apocalypse (4th Edition), pg. 104