Plasma Repeater

The Plasma Repeater, known to the Covenant as the Longarm Plasma Rifle and classified by the UNSC as the Type-27 DER or the Type-51 DER/I, is a plasma-based directed energy weapon issued to shock troops and barrier troops prior to the Great Schism. It would go on to become one of the most widely-issued plasma weapons to be procured by the Phoenix Initiative.

Development
The plasma repeater as a distinct class of weapons is less than a century old, though some design details date back to the earliest plasma weapons used by the Covenant. Plasma weapons used by the Sangheili prior to the Writ of Union were either vehicle-mounted or shoulder-fired affairs.

After the Prophets' expertise was brought to weaponmaking, weapons that could be classified as infantry rifles were produced. These weapons were heavy, and rarely shorter than two meters in overall length. It took centuries of miniaturization for a compact plasma weapon less than a meter long to be introduced, and the modern plasma rifle would take another thousand years.

A quirk of the Sangheili psychology is that they prefer to stay light and nimble on the battlefield. They prefer to trade range and firepower to retain that mobility, relying on vehicle or squire support to destroy targets at range or behind cover. Skilled weaponsmiths spent centuries streamlining the old plasma weapons, and many of those lessons would go into the making of the plasma repeater.

The true origin of the plasma repeater lies in a battle fought in 2397, during the conclusive campaign of the Srantakai Succession Crisis. Several hundred warriors sworn to the service of Dako Vao 'Srantakai were sent into the rebellious island of Lhezem's Mission. Inserted by drop pods, their orders were to disable the coastal defense batteries and prepare the way for a proper invasion. They failed. Their position was betrayed to the usurper before they had landed, and the defenders were upon them before they could regroup. The warriors were forced away from the beaches and into the highlands, fighting for weeks before they could be relieved.

Vusan 'Hadam was one of the surviving warriors, and only barely. He was nearly shot down during the landing and lost a leg in later fighting, escaping capture on both occasions by the skin of his teeth. He was convinced that the whole debacle could have been salvaged, but the warriors were too lightly armed to make a difference. His opinion was not well-received, for it is the mark of a poor warrior to blame his weapons. The twin stigmas of failure and blame-shifting would follow Vusan forever, and it took half of the rest of his life to secure an apprenticeship with a weaponmaker of Ghienimeno Ayma.

Specifications
Vusan 'Hadam's desire for the plasma repeater was to marry power, speed, and accuracy, to make up for the common plasma rifle's lack of sufficient power and reach. While some plasma turrets could be carried by hand and used apart from their regenerative tripods, they were too cumbersome to be used that way. Worse, plasma turrets have a wide beaten zone, wasting valuable shots. Vusan proclaimed that his weapon would be like a rapier, reaching far and striking true.

Accordingly, the plasma repeater has an inherent accuracy on par with a tuned plasma rifle, on top of the accuracy afforded to it by its longer, two-handed design. A plasma repeater, carried in one hand and stabilized by the off hand, points far more naturally than any single-handed weapon ever will. Additionally, the weapon is capable of projecting coherent plasma two to three times as far as a plasma rifle.

Power comes at a price, and with plasma weapons, the price of power is heat generation. This is, indeed, what every weaponmaster told Vusan would be his stumbling stone, and Vusan agreed. He was a warrior, after all, and he knew how an ill-timed overheat could interrupt the ebb-and-flow of combat, and leave a warrior defenseless. A considerable amount of the plasma repeater's bulk is devoted to sinking heat away from delicate components, but Vusan found an elegant solution. Borrowing designs from heavy weapons mounted on vehicles and starships, he tied the plasma generating components to the heat management system in such a way that their tempo decreased in proportion to the residual heat. In other words, the weapon could never cross a critical heat threshold, and the decision to vent waste heat was placed completely under control of the operator.

This innovation earned as much scorn as it earned praise, which was a high water mark for Vusan. It may stand as his greatest contribution to the field of firearms design, but it was a costly one. The active and passive cooldown systems attracted the attentions of both the Ministry of Instrumentality and the Ministry of Fortitude, who spent two decades arguing whether Vusan had left the bounds of allowable innovation. Vusan, for his part, continued to streamline his design and consult with warriors and weaponsmiths alike as to their wisdom.

Qikost-pattern
A licensed version created by the Merchants of Qikost, this design pattern had a cheaper, simplified construction that better served the needs of mass production, with a sturdier construction to better handle the need of combat. The Qikost-pattern was widely supplied to legions deployed in the Human-Covenant War, making it by far the most common type of plasma repeater encountered by UNSC forces.

M567 squad automatic weapons / directed energy
Although the Phoenix Initiative had adopted the Qikost-pattern plasma repeater in 2562, the various issues human operators had with using a weapon designed for Sangheili physiology and Covenant technology meant that it was never going to be a practical weapon for long. Not only were there the obvious ergonomic problems, but its reliance on a heads-up display for aiming and bulky recharging stations restricted where it could be used and deployed. As a result, the Phoenix Initiative issued a contract for a lighter, more permanent replacement for their plasma repeaters.

This eventually resulted in the M567 SAW/DE, a project that saw the Misriah Armory collaborate with technical experts from the Worldly Guilds of Akurr-Zufam. The final design still resembled the original plasma repeater, as the need to convert existing weapons meant that they could not implement radical changes that drastically affected its profile. All the grips were replaced with those designed for human hands, and a permanent stock with a cheekrest was added to better control recoil. Reports of troopers being burned while firing plasma weapons during the Great War saw the foregrip further protected with sacrificial heat guards. Three Misriah rails - one on top, and another on each side - that could accommodate most standard-issue attachments and scopes. The uppermost rail also incorporated a small LED screen in its base that conveyed both heat and ammunition status. There was a set of iron sights, with a three-position aperture for 50, 150, and 300 meter ranges. The last addition was four-position selector switch, which had options for off, safe, semi-automatic, and automatic fire.

The M567 had been constantly reworked over its lifespan, with several distinct variants being spawned:
 * The XM566 was the model submitted to trials for both the UNSC and the Phoenix Initiative. This version lacked a handful of features, including the Misriah rails and sacrificial heat guards. It also trialed a magazine system where both the battery and plasma canisters could be replaced, but this suffered from safety and weight issues.
 * The M567A was the first production model.
 * The M567B used ideas that could not be used before due to contract requirements. It was about 20% lighter and somewhat smaller than the original A model, thanks to the use of a streamlined alfoa frame. The drop in durability (which included reports of melting under constant fire) made them unpopular.
 * The M567C built upon the improvements of the B model. It was again lighter and smaller, but also now reincorporated the replaceable batteries in a combo system. A host of other improvements eventually saw it replacing all previous models.
 * The XM571, which was a prototype that was turned into a plasma shotgun for Hellbringers.

Service History
The longarm plasma rifle was blessed by the Ministry of Fortitude shortly before the Seventh Age of Conversion, and the first weapons to be produced by the Iruiru Armory were indeed used in the conquest of the Jiralhanae worlds, but only in handful of engagements. Vusan 'Hadam considered this to be a poor debut for his weapon. The plasma repeater was never meant to replace the plasma rifle, but it was meant to overmatch it, allowing small groups of well-armed warriors to engage many times their number with a decisive advantage. The Jiralhanae were poorly armed with plasma weapons, and Sangheili strike teams were rarely at a disadvantage.

The next few decades saw only sporadic use of the plasma repeater. Many brush wars broke out on the frontier, and a few crises close to the Sunlit Worlds, but none prominent enough to catch Vusan's attention. He went to his grave without seeing his design vindicated in a war, even though he was as convinced of its potential as he was in imminence of a great war.

The Human-Covenant War was the first conflict that would see intense use of the plasma repeater, though not in the conflict that Vusan envisioned. Instead of plasma rifles, the plasma repeater and the warriors who bore it were fighting Humans with ballistic weapons. These ballistic weapons had a greater reach and accuracy than plasma rifles, by necessity, and so the overmatch effect that Vusan hoped for did not happen. Still, the plasma repeater received its baptism in fire, being carried into battle by Zealots and strike teams alike.

The weapon was also issued to guards of the Ministry of Preservation, many of whom oversaw penal battalions and encouraged the criminal and the heretical to earn their redemption. Indeed, the order placed by Preservation would fully occupy the Iruiran line for fourteen years. As the weaponsmiths of Iruiru were uninterested in expanding their production, the Merchants of Qikost licensed the design and produced a version of their own. The Qikost pattern has a number of design changes to improve the weapon's durability, and would eventually come to be known to the UNSC as the T-51 Plasma Repeater.

The first run was acquired by a legion under the command of Thel 'Vadamee, which issued the weapon to section commanders. This was one of the first experiments in issuing the longarm plasma rifle as a generalist weapon, and could have been the first bold step in a future that its designer had never dreamed of, a future where the plasma repeater supplanted the plasma rifle or served as an equal. But opinions on the weapon were still sharply divided, and many warriors returned the weapon for the plasma rifle and carbines that they knew well. The surplus repeaters fell into the hands of some units, and even a large number of Jiralhanae janissaries.

During the Great Schism and the Blooding Years that followed, the plasma repeater finally came into its own. When Sangheili turned against Jiralhanae, and finally when the Sangheili turned on each other, the plasma repeater's qualities shone through. Many Sangheili preferred to stay with the weapons they knew, but few willingly went up against such a weapon, knowing that they were at a disadvantage of reach and power.

A strange footnote is that the plasma repeater was the first plasma weapon to be procured by the Phoenix Initiative. While plasma pistols and rifles were purchased before, these were often wholesale battlefield salvage, or bought secondhand from units that were trading up. When the Phoenix Initiative finally had the means and opportunity to buy directly from Covenant manufacturers in 2562, they bought fifteen thousand T-51 plasma repeaters from the Merchants of Qikost and issued them as squad support weapons.