Halo Alpha
Halo Alpha

The Type-51 Directed Energy Rifle/Improved (T51 DER/I),[2] more commonly known as a Plasma Repeater, is a plasma-based Directed Energy Weapon used by what used to be the Covenant Empire, specifically the Sangheili and Jiralhanae, during the Fall of Reach in August 2552. The weapon also saw action in the post-war years in the hands of Jul 'Mdama's Covenant.


Plasma repeater

Blueprint of the Plasma Repeater

The weapon's rate of fire will slow as it is fired and the weapon heats up. This can be solved by manually venting the rifle with the reload button, which can be done all at once or gradually. However, as the weapon overheats and the rate of fire slows, the accuracy of the weapon will increase.[3]

It is very likely that the Type-51 DER is either new to the Covenant arsenal or it is a branch-specific weapon, as it has only been encountered by the UNSC very recently and only in very limited numbers.[2]

Differences from Plasma Rifle[]

  • Each shot of the Plasma Repeater is 0.5% of the battery, making a total of 200 shots possible. Each shot from the Plasma Rifle is 0.25%, for a total of 400 shots possible.
  • The Plasma Repeater takes 18 shots to kill a Spartan, while only 16 are needed with the Plasma Rifle.
  • The bolts fired from the Plasma Repeater travel faster than those of the Plasma Rifle (at 50.00 meters, the Repeater's shots take .5 seconds to reach the target, while the Plasma Rifle's take .6 seconds).
  • The bolts of the Plasma Repeater have a purple hue, in contrast to the blue hue of those from the Plasma Rifle.
  • The firing rate of the Plasma Repeater decreases over time; the Plasma Rifle's increases.
  • The accuracy of the Plasma Repeater increases the longer it is fired (due to the decreasing ROF); the Plasma Rifle's remains constant.
  • The Plasma Repeater can be manually cooled, either all at once or in several intervals, while the Plasma Rifle is forced to vent excess heat all at once.
  • The Plasma Repeater features aim assist for the Sangheili, but the Plasma Rifle lacks such targeting aid.


  • According to Bungie, the Plasma Repeater is the Covenant's equivalent to the UNSC's MA5 Series.[4]
  • The weapon was designed primarily for Multiplayer for balancing purposes, but it also appears in Halo: Reach's Campaign and Firefight,[4] appearing before the Plasma Rifle does.
  • The Plasma Repeater actually never overheats, building up heat which slows its rate of fire and accuracy until it is either vented or runs out of battery. This makes it one of the few battery-operated Covenant weapons to not be burdened with a necessary cool-down.
  • There is an odd event that can be performed on the Plasma Repeater. In a Custom Game, Firefight or Forge, set Infinite Ammo to "Bottomless Clip" so it never loses fire rate. Get a Plasma Repeater and fire it non-stop. The reticle will bloom far beyond the center of the screen. Once the reticle blooms to a certain point, it will reset itself to the middle of the screen again. However, ceasing fire will cause the reticle to move to the center and then reset to the edges of the screen, then slowly move back to its original place. It is unknown why this occurs, but is most likely a glitch. It also greatly increases the fire rate, giving it one of the fastest fire rates in Halo: Reach, and a little more accuracy. If the player does not continue to fire for a period of time, the reticle will reset, doing the whole blooming process backwards.
  • After the reticle resets, the bloom will stop. However, if continuous fire is maintained for several minutes, the bloom will start again, but slower than the first round. There is an infinite loop of this happening. This is not a glitch (problem or error in programming). It occurs because the algorithm for controlling the reticle bloom of the Plasma Repeater only expands the reticle with no programmed end-point. This results in the cross hairs growing further apart until they are outside the programmed screen size. Then, the cross hairs revert to the centre and start blooming again. The bloom gets faster each time because the game tries to show the crosshairs moving an increasingly great distance outside the screen, as it speeds up the bloom. The reticle resets because eventually the speed of the crosshair movement makes the line move about one screen per frame, so they appear perpetually in the same position. A similar effect can be obtained by filming a disc spinning with RPMs equal to 60 x the FPS (Frames Per Screen) of the camera. The bloom resets because the speed exceeds the 1 Frame Per Screen value.
  • If fire is continued until the reticle resets itself, the bloom speed will become faster and faster. Once the reticle resets to the centre, your firing will become much more accurate.
  • The Plasma Repeater, along with the Focus Rifle and Needle weapons, are the only four Covenant weapons to do more damage to health than shielding.
  • In early builds of Halo: Spartan Assault, the Plasma Repeater had the same sound as Halo 4's Storm Rifle.[5] In the final version, the Plasma Repeater has its normal sound.
  • Although it is never featured in the book, the 2010 re-release cover of Halo: First Strike shows a Spartan-II wielding a Plasma Repeater.




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