Halo Alpha
Halo Alpha

I believe that the sound of racking the pump of a shotgun is universally recognized as 'kiss your ass goodbye.'
— Anonymous E2-BAG/1/7 serviceman

The M90 Close Assault Weapon System[2][3][4] (M90 CAWS) is the UNSC's primary shotgun and is one of the most effective close-range infantry weapons used by front line forces.

Design Details[]


M90 schematic.

The M90 Shotgun is a pump-action, magazine-fed, dual tubular non-detachable type weapon designed from the M45E Tactical Shotgun.[5] The Weapon System Technologies DTM series shotgun is the most common shotgun employed by UNSC Special Forces, law enforcement agencies, and sportsmen. The M90 has been in service for over 27 years and its design has changed very little throughout its service.

The M90’s immense power, ease of use, and reduced capacity for puncturing the hulls of spacecraft over many other UNSC weapon systems with standard 0000 (.38 cal pellets) ammunition are greatly appreciated. The M90 is often employed in urban conditions where the tight spaces are conducive to the shotgun's wide spray for defensive purposes and CQC.

The military issued DTM series comes standard with an adjustable stock and pistol grip, although there are different models like the WST DTM/LE model which has a solid stock and no pistol grip. The DTM series of shotguns are available in 20-gauge and 10-gauge for the civilian market. The 8-gauge is only sold to law enforcement and military agencies.


Main Article: Soellkraft 8 Gauge Shell

The M90 Shotgun uses the large Soellkraft 8 Gauge Shell. Recoil is relatively low.[2] It can hold incendiary rounds, rifle slugs, flechettes, and a variety of other forms of ammunition, but these special shells are seldom used and do not appear in any of the games.


The combined force of each of the fifteen spreading pellets per shot does a significant amount of damage against almost any type of infantry, and the shell's widespread in certain situations can inflict shrapnel damage to multiple infantry. A near miss can still inflict grievous damage; the M90 Shotgun's powerful 8 gauge shell can punch through armor and Energy Shields easily, making the M90 a great weapon for taking on heavily armored infantry and lightly armored vehicles. The M90's top-loading system allows a user to reload the shotgun with speed and ease for quick firing.


While extremely devastating at close quarters combat, the M90 is rendered virtually useless at extreme ranges, and should, therefore, be used in conjunction with a medium or long-range weapon. The shotgun's pattern is extremely loose, and fans out quickly, thus at farther ranges, only a few pellets out of the 15 might hit.

The M90, being a pump-action shotgun, must be reloaded after every shot before it can be fired again, so a user missing enemies may as well be a death sentence; the M90 must also be reloaded shell by shell and does not use any type of external magazine. This can make reloading time-consuming when in combat situations, but it is useful to be able to interrupt the reloading and shoot after you load a shell. In close-quarter situations, the widespread of the shell can potentially harm friendly infantry if the shotgun is fired indiscriminately.



  • One of the most dominating weapons in the Halo Trilogy, the Shotgun shows its most effective side in The Library in Halo: Combat Evolved, in Sacred Icon in Halo 2 and Cortana in Halo 3.
  • This weapon is easily the best choice in the game for taking out powerful enemies such as groups of Flood Combat Forms, Sangheili, and Jiralhanae. Even on Halo: Combat Evolved Heroic difficulty, it is possible to take out shielded Sangheili with as few as two shells, and only on Legendary do the Flood become capable of surviving a direct hit from the shotgun.
  • In Halo: Combat Evolved, you can perform what players call the "speed pump." In this method, the player must reload the shotgun almost instantly after firing each shot. After each time he/she repeats this procedure, the shotgun will be reloaded faster than the normal rate. As a result, the shotgun will inflict a seemingly unstoppable barrage of projectiles until there are no longer any shells left to spare. This method is extremely useful in the level, The Library, as well as the remainder of the levels after it.
  • In Halo 2, Jiralhanae, Sangheili High Councilors and Sangheili Ultra are the only enemies that can survive a point-blank shotgun blast on Normal difficulty. Mgalekgolo can be killed by shooting directly into the exposed orange Lekgolo. However, on Legendary difficulty, any rank higher than a Sangheili Minor's shielding and health can withstand a point-blank shotgun blast. Beware, for the Flood can wield shotguns to devastating effect since they have an extremely long jumping range.
  • In Halo: Combat Evolved, on easy difficulty, a Banshee can be destroyed if shot at point-blank range by an M90.


  • The shotgun's effectiveness in multiplayer games varies depending on the terrain. In tight spaces, the shotgun is almost unstoppable, even by the Energy Sword because of the Sword's slight delay between pressing the trigger and the slash of the sword.
  • Carry the shotgun with a weapon that is very effective at medium and above ranges, such as a Sniper Rifle or BR55 Service Rifle.
  • Continuous firing by using the magazine and loading one shell then firing does not affect the rate of fire significantly, prompting a few players to employ a tactic dubbed "shotgun sniping" as suppressive fire across medium-sized maps.
  • The Shotgun can finish enemies off safely and quickly by shooting them at a decently close range, then striking them with a melee attack immediately afterwards, guaranteeing an instant kill.
  • Defend a teammate who is mostly immobile, such as a sniper or Oddball carrier.

Differences among games[]

Halo: Combat Evolved[]


Holding the M90.

The M90's Mk. 1 incarnation in Halo: Combat Evolved is arguably the strongest version. It can hold 12 shells, and the player can carry up to 60 more shells for a total of 72 shells. It has the longest effective range of all the three models, and its fifteen tungsten pellets can kill or injure targets at short to medium ranges. Although it is more likely to kill a closer ranged enemy as the shotgun is weak on further distanced enemies, the shotgun could also kill nearly any infantry target at point-blank range. It even has the capabilities to take on lightly armored vehicles, such as the Ghost effectively.

Players could hold the trigger button down for continuous fire. To melee, the player swings the shotgun up and brings the butt of the weapon on someone's head/front. If the player fires the entire magazine or if the player picks up a Shotgun without a full magazine and fires it empty, the character model will rack the shotgun's pump after reloading, although most players usually opted to reload after every shot. It reloads more quickly than in Halo 2.

Halo 2[]

In Halo 2, the M90 Mk. 2 differed significantly from its predecessor. The only aesthetic difference is that the iron sights are green instead of blue. The melee attack is much faster than in the original game, and the weapon in slung horizontally as well as vertically. Its performance is also drastically different as it can not kill targets at more than a few feet away, though a quick shoot-melee combo would usually kill an enemy very quickly.

The player can only carry 36 spare shells for a total of 48 shells. Unlike the previous version, it has almost no stopping power when used against vehicles, and like before, with the range decrease, its effectiveness against the Flood was reduced slightly. It probably took this change as Bungie introduced the Energy Sword as a usable weapon, and wanted to "even the odds." The weapon's action does not cycle after reloading, unlike the previous iteration of the M90.

Halo 3 and Halo 3: ODST[]

The M90A is used in Halo 3 and Halo 3: ODST. There are a variety of graphical and gameplay changes from the previous models. The blue iron-sights have been reintroduced, it has a longer barrel and the flashlight is now mounted on the side. Unlike the older models which had a 12 shell magazine, the M90A only has a 6-shell magazine. The player can carry 30 spare shells for a total of 36 shells. To make up for this, its effective range is far greater than that of the Halo 2 incarnation, as it can kill targets at two or even three times the range, depending on their health.

The rack is always pumped after reloading, even though this would eject a shell if any were already loaded. Like in Halo: Combat Evolved, the M90A is once again a powerful weapon for use against the Flood because of its increase in range and power, though the M90A may still require a player to shoot and melee a Flood target, depending on the type.

UNSC Remarks[]

  • “The kick is milder with the As—not that it was that bad, to begin with—sometimes progress just seems like change, if you catch my meaning.”
  • “The adjustable stock on the M90 works just fine, but I’ve got a soft spot in my heart for the DTM/LE model—old habits die hard, I guess."
  • “I think the jury is still out on whether it means ‘STFU and STFD’ or ‘you ain’t gonna make it.'”
  • “The action I saw against the Flood on Delta Halo was pretty limited—thankfully—and you would think that the M90 would be the ultimate anti-Flood weapon, right? Except that a shotgun is effective because it delivers a massive shock to a delicately balanced system of organs and the Flood doesn’t have that delicately balanced system of organs—it’s like shooting a mike foxtrot tree! All you can hope to do is disassemble them as rapidly as possible in the correct order.”
  • “The shotgun is a specialist weapon—it has its uses, but they are limited. Maybe it is more accurate to call it a tool, as opposed to a weapon?”
  • "I remember using the M90 when I was in Sigma Octanus IV. I was in a hotel with a bunch of buddies, doing some mopping-up, and at one time I managed to blow an Elite's head off. I mean, I blew it off. I couldn't even imagine what that felt like, but all the same, he got what he deserved."


  • The M90 has a wide variety of slang associated with it, such as: waste 'em, deck clearer, The Hammer, Mop, Broom, Universal Translator, High Stick, Thunderer, Betsy, Equalizer, The Okay-47 (a reference to the AK-47), and many, many others according to the Halo Encyclopedia.[6]
  • In Halo: Combat Evolved and Halo 2, it is said to be a magazine-fed weapon, which has caused much speculation as to whether there was a typo. This confusion is a common misconception, however, since Shotguns have an internal, non-detachable magazine which is different than box magazines used by typical Assault rifles and pistols.
  • In reality, the racking of the pump would take little effort. If the racking was not exaggerated, the cycle time would be 50% faster.
  • In Halo: The Flood, it is stated that the M90 fires a twelve gauge shell, whereas in the Halo game manuals it states that the M90 fires an eight gauge shell.
  • Miranda Keyes is the only known human to dual-wields a shotgun with another weapon.
  • In the Halo Legends episode The Package, Kelly-087 is seen firing the M90 in semi-automatic. This suggests that the shotgun is a selective-fire weapon, or just overlooked, like many other details in The Package.
  • In Halo: Combat Evolved, if you look at a discarded shell with a sniper rifle it will have a grinning hippo with the words for hippos everywhere on it.
  • In Halo 2: Anniversary, if the Arbiter (or Chief with the Envy skull) goes invisible, a shotgun shell can be seen in the chamber.




  1. Halo: CEA Kinect Voice Library
  2. 2.0 2.1 Bungie.net
  3. The Art of Halo
  4. Halo Encyclopedia, page 310
  5. Halo: Combat Evolved Anniversary, Kinect Library, Shotgun, "Weapon System Technology recreated a more economical and practical version of the M45E in their M90 Close Assault Weapon System"
  6. Sybex Halo PC Strategy Guide, page 19

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