Possibly the oldest type of directed energy weapon used by any race, save the Forerunners, the heavy linear Particle Cannon had been in use for as long as the Allegiance existed. These earlier versions, however, were nowhere near as powerful as more modern variants, nor numerous or capable of such rates of fire. This was mainly because Zero-Point energy, the lifeblood of all Allegiance vessels, had not been refined nearly enough to fit a generator inside a warship. Finally, after centuries of investment and development, a breakthrough came with the HMS Marchestra, a huge ship that needed something as huge as a zero-point generator to power it. Subsequently they were refined to a point where all but the smallest Allegiance warships were powered by one, and warship development skyrocketed as the near-limitless energy source pushed the boundaries of what ships could do. A major consequence of this was the development of more than one linear Particle Cannon mounted to ships, with more destructive power, longer range and better rate of fire than ever before. While quite an old model, the DDP-278 was still able to hold its own, even in the fast changing technological world of the 27th century. Due to be replaced in the mid 2700s, they remained in frontline service for over a century longer, a direct result of the Swarm War.
The weapons were utilised as a ship's first attacking option, its primary weapon. They were mounted directly to a warship's keel, with the barrel protruding from the ship's prow. This was necessary due to the size of the weapons, but limited their field of fire. They were extremely long ranged, able to engage targets at around 20 light minutes (or 360,000,000km) away, far beyond the reach of any comparable weapons. They were a potent anti armour weapon, able to deplete or pierce shields and then tear through armour and cleave ships in two in mere small salvos. A single cannon could fire seven times before needing to pause to cool, but it could pause at any time in between. After a full firing sequence, the cannon would remain inoperable for three minutes at least before the barrel was cool enough to allow another firing sequence. The group of six cannons were arranged in 'fire groups' of three groups of two, each cannon firing alternately. In this way, a fire group could fire 14 shots before needing to pause. The three groups could together fire 42 shots before needing to pause, although they could extend this by leaving slightly longer periods of time between each shot. They had a range of around 360,000,000km, or approximately 20 light minutes. The weapon's faster-than-light nature meant that they had no chance of missing their target, even over astronomical ranges.
|Weaponry of The Royal Allegiance during the Swarm War|
|Infantry Heavy Weapons|
|Light Vehicle Weapons|
|Heavy Vehicle Weapons|
|Rockets and Missiles|
| Starship Weapons |
M421 General Purpose Cannon | M119 Heavy Naval Cannon | M125 Missile Launcher | M252 Area/Point Defence Weapon System M253 Area/Point Defence Weapon System | MD12 Particle Cannon | MG9 Heavy Particle Cannon | DDP-278 Linear Particle Cannon