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 serviceman

The Type-25 Directed Energy Rifle, more commonly known as the Plasma Rifle, is a Covenant infantry weapon.

Overview
The Type-25 DER is the primary weapon of the Covenant's officer corps, standard issue to Sangheili and Jiralhanae, lower caste species within the Covenant who have attained significant rank within the Covenant military are issued this weapon during operations. The Type-25 DER was one of the earliest and most frequently encountered Covenant plasma weapon. It occupies a role very similar to the human assault rifle. In the post-war era the T25 DER is still the primary weapon of Thel 'Vadam's Covenant faction.

Design details
The Plasma Rifle consists of two large semi-automatic weapons welded together one on top, the other beneath. The pair of curved bodies are joined via the trigger guard. Placed atop one another, these projectors fire in a "stagger" pattern taking the slow automatic fire of each individual collimator and combining it, this design allows a faster rate of fire and more rounds per second. The side of the weapon has a small temperature gauge. This visually informs the wielder how close the weapon is to overheating. The rifle, like most Covenant weapons, is smooth and aerodynamic, almost organic in appearance. Covenant technology possesses no instrumentality, meaning none of the surface controls or triggers connect in any way human scientists can understand.

Ammunition
The Plasma Rifle is a directed energy weapon that uses superheated ionized gas as ammunition instead of the humans' conventional projectile ammunition. While human military experts and scientists do not understand how Covenant plasma weapons work, or how they are recharged, they are able to identify the components of the feed system. 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 360~540 rounds per minute. Unlike the Plasma Pistol, the Plasma rifle is capable of 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 either a Plasma Pistol or Plasma Rifle will kill a light or unarmored target.

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 is far more powerful than its Halo 2 and Halo 3 counterparts; also the weapon holds the unique ability to stun opponents that were hit by 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 Ghosts and Banshees.

In Halo: Combat Evolved Anniversary, the Plasma Rifle utilises 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 is not as powerful as its predecessor and lacks the ability to stun. In addition it is also noticeably less accurate, especially at long range. These drawbacks are compensated by a higher rate of fire 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. A Plasma Rifle is much more efficient at taking out the shields of an opponent compared with ballistic weaponry, but it is less efficient against flesh. 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 more powerful than its Halo 2 counterpart, but is still weaker than the Halo: Combat Evolved version. Like most of the plasma weapons featured in Halo 3, they have the same overheating rate as their predecessors. To better balance the weapon, the Plasma Rifle now fires as fast as the Brute Plasma Rifle did in Halo 2. 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 now seem to travel faster than from previous games, 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 Halo 3 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. The Plasma Rifle makes a very prominent appearance in the campaign and is wielded by Sangheili, Unggoy and occassionally 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.

UNSC remarks

 * “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.”
 * “I realize that it uses a battery instead of a magazine, but nobody has figured out how to swap it or recharge it yet? Don’t we have scientists working for us or something?”
 * “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.”
 * “You know, it looks delicate and so you feel like you need to hold it kind of gingerly—but then you see an Elite crack a Bravo Kilo's head with one—the things are built tough.”
 * “Yeah, and I’ve seen some Elites swinging two of them around like it was nothing—scary shit.”
 * "These things are huge—but I guess the Elites are, too—so it sorta makes sense."

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.
 * Modified Plasma Rifles appeared in Halo: The Cole Protocol. They featured ammo readouts with Arabic numerals and pop-up sights, and were sold to humans from Kig-yar black markets in The Rubble. This was discovered by the rest of the Covenant and seen as heresy, when it was really a plan devised by the Prophet of Truth to find the location of Earth.
 * 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.

List of appearances

 * Halo: The Fall of Reach
 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo: First Strike
 * Halo 2
 * Another Day at the Beach
 * 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
 * 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 (Prologue Only)
 * Halo: Spartan Assault
 * Halo: Mortal Dictata
 * Halo 2 Anniversary
 * ''Terminals