Assault Cannon

The assault cannon is a six-barreled, self-loading rotary Autocannon, effective against infantry targets and light vehicles at close to medium range. It is a medium calibre rotary autocannon, with its 6 barrels cycled by an electric motor past a single chamber. The weapon's large size and tremendous fire rate require a special means to sustain, so the assault cannon is normally mounted on vehicles or walkers such as Dreadnoughts, or specially damped and fitted to Space Marine Terminator Armour. It is also commonly used by the Blood Angels Space Marines as their close assault Baal Predator tanks sport a twin-linked assault cannon in the turret. The anti-infantry Land Raider Crusader also has a similar dual assault cannon mount (while the standard Land Raider has a dual Heavy Bolter). The Razorback also has the option to use a twin-linked assault cannon. Although the assault cannon lacks the range of other rapid-fire guns such as the Heavy Bolter and the Autocannon, its enormous rate of fire enables it to literally shred its way through most targets, punishing them with a hundred rounds per second. Assault cannons are extremely potent at medium to close range, against armoured infantry and moderately armoured vehicles, while Heavy Bolters are only effective against lightly armoured targets and Autocannons have a slower firing rate. The assault cannon epitomizes the deadliness of elite Terminator Squads who teleport behind the enemy's front line and open up fully-automatic fire, spreading carnage and terror. Assault cannons are used by Planetary Defense Forces on rare occasions as a stand-mounted defensive weapon, and are also found on the Destroyer variant of the Marauder bomber.

The assault cannon was developed after the Horus Heresy as a replacement for the autocannon. Introduced during the Mark IIIA phase of Terminator Armour development, this weapon is the standard alternative to the heavy flamer as a Terminator Squad's special weapon. Its design has changed little in 10 millennia, retaining the distinctively long, cylindrical, rotating barrels. Although it lacks the range of the autocannon and many other heavy weapons, the assault cannon is a fearsome weapon when used in the close range role it was designed for. The weapon is prone to overheating and jams due to its high rate of fire - the number of rounds fired per second are counted in the hundreds. The barrels and other firing components are made of a heat-dispersing ceramic/metallic alloy, helping the weapon to withstand the intense heat generated by its high rate of fire. Despite this, the barrels still reach temperatures of over 300°F. Due to the high rate of wear on the barrels, the barrels are replaced after every mission. Motor and barrel failure are common problems with the assault cannon, making the weapon prone to jamming during sustained bursts. The weight and complexity of the mechanism, and the heavy recoil generated means that the assault cannon requires a stable firing platform. The weapon is not considered man-portable, however the powerful servos, recoil compensators and stabilisers built into Terminator Armour allows the elite Astartes Terminator Squads to carry the weapon into battle. The assault cannon is well suited to the battlefield role of Terminator Squads, providing a massive rate of fire which often compensates for the enemies' vast superiority in numbers. In confined environments providing long corridors of fire, such as Space Hulks and the hive cities of hive worlds, the assault cannon is invaluable. The high rate of fire makes the assault cannon unsuitable for extended engagements when used by Terminators, as the ammunition carried is quickly exhausted. This drawback is negated in vehicle and Dreadnought mountings, where ammunition storage capacity is far greater. The standard ammunition fired by an assault cannon is a cased round, comprising a dense metallic core covered in a non-metallic composite sheath with a diamantine tip. This provides excellent penetration capabilities against light and personal armour. It has long been reported by the Astartes that the assault cannon's massive rate of fire can allow it to chew through armour that would normally be impenetrable to a weapon of its calibre. Extensive testing by the Adeptus Mechanicus supported this observation, and Astartes targeting doctrines have been officially amended to recognise this attribute. The logistic shortcomings of the assault cannon are far outweighed by its destructiveness in combat and its effect on enemy morale.