Okarda'phaa-pattern plasma rifle

"You know, it looks delicate and so you feel like you need to hold it kinda gingerly—but then you see an Elite crack a Bravo Kilo's head with one—the things are built tough."

- Anonymous UNSC serviceman

The Type-25 Directed Energy Rifle (T25 DER), more commonly known as the plasma rifle or plasma gun, is a fully automatic rifle, formerly serving as a Covenant infantry weapon. The Type-25 DER was the primary weapon of the Covenant's officer corps, standard-issue to Sangheili and Jiralhanae. However, lower-caste species within the Covenant who had attained significant rank within the Covenant military were also issued this weapon during operations. The Type-25 DER was one of the earliest and most frequently encountered Covenant plasma weapons. It occupies a role very similar to the human assault rifle.

The earliest iterations of the plasma rifle were in use by the Sangheili warrior class for millennia, long before the Covenant itself was established. Human researchers of the UNSC's Office of Naval Intelligence believe that the plasma rifle's current design dates back at least five hundred years, with only slight modifications made to the rifle over time. In the post-Covenant War era, though, it has been largely phased out for the Type-55 storm rifle.

Design details
"It's got no sight-line, it's awkward to hold, and if it overheats it'll cook the hair right off of your wrists."

- Anonymous UNSC serviceman

The Type-25 plasma rifle is a battery-powered directed-energy weapon that is capable of fully automatic fire. The two segmented portions of the rifle function as large plasma generator subassemblies. The pair of curved bodies are joined via the trigger guard, creating the rifle's distinctive smooth, streamlined shape. The rifle, like most Covenant weapons, is smooth and aerodynamic, almost organic in appearance. The plasma rifle's design has only changed slightly over its centuries of service. The weapon's contemporary design was the result of Forerunner technology, Sangheili craftsmanship, and San'Shyuum artistry. The plasma rifle's design was noted to be jawlike, a design that perhaps unconsciously mimicked a Sangheili's mandibles.

Placed atop one another, the rifle's generators fire in a "stagger" pattern taking the slow automatic fire of each individual collimator and combining it at the charging and accelerator poles. This design allows for a faster rate of fire and more rounds per second. Despite the efficiency of the plasma rifle's design, a significant amount of waste heat is produced by the rifle's generators. As a result, the wielder is forced to fire short, controlled bursts or risk overheating; the latter of which is a tendency of the weapon. The side of the weapon has a small temperature gauge. This visually informs the wielder how close the weapon is to overheating.

Covenant technology possesses no instrumentality, meaning none of the surface controls or triggers connect in any way human scientists can understand. By late 2552, these scientists were awaiting treaty negotiations with the Sangheili with the aim of receiving specifics of the plasma rifle.

Ammunition
"The Type-25 DER has no recoil to speak of; it tears up shields and you can shoot the thing all day long—it's on the heavy side though."

- Anonymous UNSC serviceman

The plasma rifle is a directed-energy weapon that uses superheated ionized gas as ammunition. The weapon's inner workings are comprised of several components, including a power cell that keeps the weapon active, powers the magnetic containment field, and carries out the firing cycle. The weapon has a power output of 100-150 KV @ 2~3 dA, and can fire between 360 and 540 rounds per minute. Unlike the Type-25 plasma pistol, the plasma rifle is capable of both semi-automatic and full automatic fire.

The lethality of the Type-25 Directed Energy Rifle is extreme. Injuries inflicted to a victim are severe third-degree burns, this type of injury destroys the outer layer of skin and the entire layer beneath; the wound is cauterized instantly upon impact. Body fluids would be subjected to flash vaporization, inducing a strain or a shock on the body after impact, fluids trapped in organs or arteries in addition to the rapid expansion of heat would cause ruptures or small explosions causing additional damage to the target. At close range two bursts from the Type-25 DER have enough thermal transfer and kinetic energy to pass through victims with ease, close-range impacts can also cause dismemberment of limbs. Near-misses can also cause injury to the target, as they produce severe burns to the area they pass; this can also cause heat trauma or heat stroke from the extreme temperatures of the bolt. Should the plasma impact an object, the impact can cause splash damage creating debris, both non-heated and heated, that may come into contact with a target, with a crippling or lethal effect. Generally two hits from a plasma rifle will kill a light-armored or unarmored target.

Variants
As with most Covenant weaponry, modifying the plasma rifle was seen as blasphemous at best, heretical at worst. This is due to the weapon's incorporation of Forerunner technology and San'Shyuum designs. However, a small quantity of plasma rifle variants have been manufactured over the years of its service history. Occasionally, influential clients and heroes of the Covenant—who were considered to be above Ministry sanction—were able to commission Sangheili artisan-armorers to produce custom variants of the plasma rifle to suit their needs.

One of the most renowned variants of the plasma rifle is the Type-25 Brute plasma rifle. Although most plasma rifles are produced by Iruiru Armory, this variant was manufactured at Sacred Promissory's assembly forges on High Charity. Ordered by the High Prophet of Truth in preparation for his genocide against the Sangheili, the variant was modified to tailor to his Jiralhanae allies' aggressive nature. The rifle was modified to increase rate of fire and damage. Had it not been for the Hierarch's blessing, these modifications to the weapon would have been deemed heretical.

In 2535, during the Human-Covenant War, several plasma rifles were modified by Kig-Yar for human use. These variants were again covertly sanctioned by the High Prophet of Truth, who had the Kig-Yar install tracking devices into the weapons with the intent of locating Earth and other human colonies. These rifles featured ammo readouts with human numerals and pop-up sights. The Kig-Yar, posing as Covenant deserters, sold these rifles to human Insurrectionist black markets in the Rubble. The plan failed when the weapons were discovered by the High Prophet of Regret and was declared to be heresy, resulting in the Hierarch ordering Zealots to end the weapon modification.

Advantages
The Plasma Rifle is a close-to-medium range weapon, and as such can inflict very high damage at that range. The rifle is extremely efficient at killing "soft" targets, while doing lethal amounts of damage to a heavily armored target. Enough infantry equipped with Type-25 rifles can halt enemy infantry advance with its ability to deliver harassing suppressive fire; this tactic is also reflected in the Covenant's combat doctrine: destroy enemy morale with harassing fire from distant or hidden snipers and intimate exposure to the alien-ness of their infantry. SPARTAN-IIs and Elites have been observed to be able to dual-wield plasma rifles, doubling their efficiency in close to medium range combat situations. The Plasma Rifle's high velocity bolt coupled with its kinetic impact to a target can temporarily stun a target like a SPARTAN-II.

Disadvantages
The Plasma Rifle, when fired continuously, overheats very quickly because of the rapid cycling, loading, ignition, and release sequence of energy; to prevent the weapon from being damaged, the Type-25 DER temporarily shuts down and opens heating vents to allow the excess heat to dissipate before the weapon reactivates. This process leaves the weapon inoperable and useless. Careless infantry who are not aware of the function of the Plasma Rifle can get themselves killed because of this.

The rifle has no known methods of restoring its battery ammunition; as such, when the battery is depleted, the rifle must be discarded or replaced. At 10% charge level, the plasma rifle will begin to misfire, this is due to the power cell's inability to deliver enough energy to start and complete the ignition and release phase of operation, hampering the operator's use of the weapon.

Although the Plasma Rifle can strike a target at longer ranges, it is not suited for long range combat, due to two distinct properties of the weapons operation. The first is the rate of thermal expansion which is determined by the rate of the bloom of the bolt. The second factor is speed: the faster the bolt goes, the farther the bolt will travel before the magnetic field begins to weaken, causing the temperature of the bolt to cool before the magnetic field becomes unstable and finally dissipates. The bolt also loses velocity and kinetic impact with longer travel distance.

Halo: Combat Evolved
The Plasma Rifle in Halo: Combat Evolved kills fully-shielded Spartans in 9 shots; the weapon also holds the unique ability to stun opponents hit by a high amount of plasma rounds: this effect greatly reduces the victim's ability to move and dodge the incoming projectiles and allows the user to easily hold the opponent in the weapon's firing arc. However, the drawback was that this effect is only felt with continuous fire. While stunned, the weapon will often overheat before the opponent is killed, especially if it is an Elite or Hunter. Despite this drawback, the stun ability is a useful and potent feature in the hands of an experienced user. Beware that the Plasma Rifle decreases in accuracy while heating up. However, firing in bursts can counteract this and is much more useful over longer ranges. In the campaign, the Plasma Rifle is best used against the Sentinels and Elites. Fully charged Plasma Rifles can be obtained by killing Elite Combat Forms or killing Elites riding on Type-32 Ghosts and Banshees.

In Halo: Combat Evolved Anniversary, the Plasma Rifle utilizes Reach 's design and features a remastered audio as well as firing effect.

Changes from Halo: Combat Evolved to Halo 2
The Plasma Rifle in Halo 2 kills fully-shielded Spartans in 18 shots and lacks the ability to stun. In addition it is also noticeably less accurate, especially at long range. These drawbacks are compensated by no longer misfiring when on low battery and the ability to dual-wield, allowing it to be paired with a wide variety of other weapons. The changes done to the weapon are directly related to the inclusion of dual-wielding for balancing purposes. The Plasma Rifle, along with many other weapons from Halo: Combat Evolved, has been tweaked to better fit the new game engine. This version of the Plasma Rifle behaves more as an SMG rather than a rifle. The Plasma Rifle now has a new firing sound effect to give it along with other plasma weapons a distinct sound to distinguish it easier. In addition to that a new variant, the Brute Plasma Rifles, is introduced.

Changes from Halo 2 to Halo 3
The Plasma Rifle in Halo 3 is much better at draining energy shields than its Halo 2 counterpart, though it still requires 18 shots to kill a fully-shielded Spartan. Plasma bolts fired by the Plasma Rifle and all other plasma weapons in Halo 3 have been graphically redesigned to have a more vivid look. The bolts travel much faster than from Halo 2, reducing the need to lead the shots at mid-to-long ranges. However it takes fewer shots of constant fire for the plasma bolts to become very inaccurate. It is considerably harder to come across the Plasma Rifle in the campaign, because of the lack of Elites and the introduction of new Brute weapons such as the Spiker.

Changes from Halo 3 to Halo: Reach
In Halo: Reach the Plasma Rifle, like the other plasma weapons in the game, have been dramatically redesigned and retooled to function closer to their Halo: Combat Evolved versions, although in Reach the absence of the stun effect and bonus headshot damage makes it less so. The Plasma Rifle makes a very prominent appearance in the campaign and is wielded by Sangheili, Unggoy and occasionally Kig-Yar. The weapon is available in Forge but is not placed on any multiplayer map by default excluding community maps. This weapon also replaced the Needler for the Armor Lock loadout in Elite Slayer. The weapon appears to fire faster but still not as fast as the Plasma Repeater. The weapons animations are far more detailed and are meant to give it a more menacing and dangerous look. Like the Plasma Pistol, the design of the weapon has changed considerably from previous games, The grip has been altered, and appears to be more ergonomic (to Elites at least) and now sports a darker blue color. The Plasma Rifle is the only weapon that is dual-wielded in Reach, with certain Sangheili seen wielding pairs of them in the Campaign and in Firefight.

Changes from Halo: Reach to Halo 2: Anniversary

 * Both plasma rifles in Halo 2: Anniversary perform nearly identical to their Halo 2 incarnation.
 * It can once again be dual-wielded.

Changes from Halo 2: Anniversary to Halo 5: Guardians

 * The plasma rifle is absent while the Brute plasma rifle is included.
 * It uses 1% battery every 3.2 shots and overheats every 16 shots nonstop.
 * It cannot be dual-wielded.
 * Rate of fire is approximately 600 rounds per minute.
 * Range and damage are significantly increased.
 * The Smart-scope mechanic has been added.

Trivia

 * In the Halo: Combat Evolved instruction booklet there is a Plasma Rifle picture over a picture of the Needler.
 * In Halo: Combat Evolved, the Plasma rifle and the Plasma Pistol use the same sound file.
 * In Halo: Combat Evolved, the Plasma Rifle has 2 shots per 1% charge, totaling 200 shots. In Halo 2 and 3, it has 4, totaling 400 shots.
 * In Halo 2, the Brutes normally wield the Brute Plasma Rifle, except in the level "The Great Journey", where Brutes driving vehicles will be found wielding the normal Plasma Rifle. Also in the level "Sacred Icon", a few dead Brutes have Plasma Rifles beside their corpses.
 * In Halo 2, when playing as the Arbiter, allies wielding Plasma Rifle have the weapon in "overheat" mode.
 * If the player remains idle for a while in Halo: Combat Evolved, the in-game character will inspect the weapon on both sides; in Halo 2 he/she will open the cooling vents; in Halo 3, he/she will pull on the top.
 * In Halo: Reach, Plasma Rifles are one of the few weapons which has a reticule that never changes size.
 * In the Original Trilogy, the Plasma Rifle's UNSC counterpart seems to be the MA5B ICWS or the M7 Caseless Submachine Gun. However, in Halo: Reach, the way a Spartan or Sangheili wield the Plasma rifle is identical when wielding an M6G magnum, even with alert carry, which implies that the Plasma rifle's counterpart is also the M6G Magnum.
 * In Halo 4, the plasma rifle is replaced by the functionally similar storm rifle which also fills a similar in-game role. This marks the first Halo game in which the plasma rifle is not present in gameplay; however, the weapon appears briefly in the Prologue cinematic. It also appears in the DLC map Pitfall as part of the Elite targeting silhouettes.
 * Until late in development of Halo: Combat Evolved (May 16, 2001), the Plasma Rifle and the Plasma Pistol had their functions switched completely. The Plasma Rifle's model had the overcharge function and lowered rate of fire. The converse is true for the Plasma Pistol.

List of appearances

 * Halo: The Fall of Reach
 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo: First Strike
 * Halo 2
 * Halo Graphic Novel
 * The Last Voyage of the Infinite Succor
 * Halo: Ghosts of Onyx
 * Halo: Uprising
 * Halo 3
 * Halo: The Cole Protocol
 * Halo Wars: Genesis
 * Halo Wars
 * Halo: Helljumper
 * Halo Legends
 * The Duel
 * Homecoming
 * Origins
 * Prototype
 * The Package
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * Headhunters
 * Halo: Blood Line
 * Remember Reach
 * Deliver Hope
 * Halo: Reach


 * Halo: Glasslands
 * Halo: Fall of Reach
 * Covenant
 * Invasion
 * Halo: Combat Evolved Anniversary
 * Halo: The Thursday War
 * Halo 4: Forward Unto Dawn
 * Halo 4
 * Halo: Spartan Assault
 * Halo: Mortal Dictata
 * Halo: Broken Circle
 * Halo 2: Anniversary
 * Terminals
 * Halo: Escalation
 * Halo: Spartan Strike
 * Halo: Last Light
 * Halo 5: Guardians
 * Halo: Ground Command
 * Halo Mythos
 * Halo Wars 2
 * Halo: Envoy
 * Halo: Legacy of Onyx
 * Halo: Collateral Damage
 * Halo: Fireteam Raven
 * Halo: Official Spartan Field Manual
 * Halo: Battle Born
 * Halo: Outpost Discovery
 * Halo: Oblivion