Plasma Weapons - Imperial History: Despite their well-known drawbacks, Plasma Weapons have remained part of the Imperium's arsenal for thousands of Terran years, since at least its inception. Such technology was far better understood during the dawn age of the Imperium, if still somewhat unsafe.By the time of the Horus Heresy in the early 31st Millennium, Plasma Weapon technology was at a dangerous phase in its development. Plasma Reactors were in widespread use, and the giant weapons mounted on Titans and space-faring vessels were a simple outgrowth of the systems needed to create the reactors.Plasma Weapons which could be carried and used by a Space Marine Legionary in power armour were still prone to overheating and leaking energised plasma onto their unfortunate users.Nonetheless the devastating power of plasma weaponry made it too potent to abandon and many Space Marine Legions utilised it in a limited fashion anyway. In the dark days of the Heresy itself, the desperate need for ever more potent armaments pushed early Plasma Weapons to the battle front more and more, regardless of the risks involved.Towards the end of the Heresy, the Tech-priests of Mars solved the immediate problems of Plasma Weapons. By slowing the recharge mode of the weapons, they found they could maintain the integrity of the magnetic field containing the energising plasma.This prevented catastrophic leaks detonating whole weapons. The slower recharge cycle also meant that overheating was kept to a minimum by the weapon's coolant system.The resulting Plasma Weapons were relatively safe and reliable, but suffered from a slow recharge rate which limited their effectiveness. Space Marine commanders were far from happy at the compromise but the number of catastrophic meltdowns experienced with the older weapons made Plasma Weapons too dangerous for the Space Marine Legions to continue using otherwise.As doctrine within the ancient Mechanicum changed, the old-style, less reliable Plasma Weapons were branded Fabrus Excommunicata, engines of destruction that had fallen from the approval of the Machine God. Within a few standard centuries, early Plasma Weapons had entirely disappeared.Such a light of reason has never shone over the Traitor Legions. They still maintain and use the old, dangerous Plasma Weapons, perhaps revelling in the raw danger of doing so. Given the contempt held for life by Heretic Astartes, it's unlikely they would be willing to trade off less firepower for a safer weapon anyway.In the 41st Millennium, it is an honour to carry such weapons into battle and be trusted to make sure every searing shot counts, though most of the weapons in use at present are relics of technology based on the ancient, less-reliable design that predated the Horus Heresy.Based on the secrets of the sacred STC database, it is a design that has never been developed or improved on by the post-Heresy Adeptus Mechanicus.Indeed, the very thought of trying to mitigate the flaws of Plasma Weapons would be repellent to the followers of the Machine God. By the grace of the Omnissiah, these weapons fulfil a role within the God-Emperor's armies, and to change this role in any way would be to invite mayhem and disorder.So Plasma Weapons are crafted just as they have been for untold centuries, each finding its way into the hands of a resolute Space Marine or an ungrateful Guardsman.