M90 shotgun

"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 is a pump-action shotgun used by the United Nations Space Command. Part of Weapon System Technologies' DTM series, the M90 is a copy of Misriah Armory's M45 Tactical Shotgun.

Design details
The M90 CAWS is functionally identical to the M45E on which it is based. It is chambered for 8 gauge ammunition, typically the Soellkraft 8 gauge magnum in lieu of the M296 Magnum used by the M45. The cartridge provides immense firepower and ease of use with little risk of penetrating spacecraft hulls. The weapon features a dual-tubular, non-detachable magazine that can be fed up to twelve shells through a top-mounted elevator. As the M90 is pump-action, spent shells are ejected each time the user works the action.

A tactical flashlight is mounted in line with the action shortly behind the muzzle. The iron sights may be colored faint blue (like the M45E's) or vibrant green. The weapon has an adjustable stock.

M90A variant
The M90A variant is similar in performance to the original M45, whereas the basic M90 is patterned after the M45E. The M90A has a magazine capacity of six shells rather than twelve, though this is compensated for by a longer barrel. The tactical light is mounted on the left of the action's grip instead of in front. The iron sights are colored blue.

Operational history
Shotguns saw prominent use during the frequent close-quarters urban combat of the Insurrection. Misriah Armory's M45 Tactical Shotgun (particularly the M45E variant) was acclaimed by its users, prompting Weapon System Technologies to develop a more economical and practical version. The resulting M90 Close Assault Weapon System is part of WST’s DTM series, which is also marketed to civilians and law enforcement agencies. Over the next several decades the M90 eclipsed the M45 in both the military and the private sector, seeing widespread use during the Human-Covenant War. However, both models continue to serve alongside one another, particularly in the UNSC Marine Corps. Jiralhanae on Installation 05 used captured M90s (along with other UNSC weapons) at the outbreak of the Great Schism.

The M90 has earned a plethora of nicknames over the course of its service life, including "waste 'em", "deck clearer", "The Hammer", " Mop", "Broom", "Universal Translator", "High Stick", "Thunderer", "Betsy", "Equalizer", and "Okay-47".

Advantages
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 wide spread in certain situations can inflict shrapnel damage to multiple infantry. A near miss can still inflict grevious 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.

Disadvantages
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 wide spread of the shell can potentially harm friendly infantry if the shotgun is fired indiscriminately.

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."
 * “Actually, 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 don’t have that delicately balanced system of organs — it’s like shooting a mike foxtrot tree! All you can really 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?”

Trivia

 * In Halo: Combat Evolved, the M90 shotgun shares its reticule with the sniper rifle and the then-PC-exclusive flamethrower.
 * In the second issue of Halo: Fall of Reach - Boot Camp, the captain of the retrieves several shotguns from a cryo chamber. In the first two panels, the shotguns appear to be M45s, though they resemble M90s in subsequent panels.
 * In Halo 2: Anniversary, if the player uses Active Camouflage while the M90 is equipped, the shells will be the only objects still visible. This could be because the shells are technically not attached to the shotgun (like the magazines in other weapons) but rather held inside the weapon until ignited and fired. This is best seen when playing as the Arbiter.
 * In Halo: Combat Evolved, the shotgun is the most effective weapon in the game against most Flood forms. A single shot is capable of killing Flood combat forms and Flood carrier forms and works best when paired with a weapon with a high-rate of fire such as an MA5B assault rifle to deal with Flood infection forms. The shotgun is still effective in later games, but not to such a degree as, starting in Halo 2, infection forms can revive deceased combat forms unless the body is destroyed. Halo: Combat Evolved lacked this resuscitation ability for the Flood.

List of appearances

 * Halo: The Fall of Reach
 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo: First Strike
 * Halo 2
 * Halo Graphic Novel
 * Breaking Quarantine
 * Halo 3
 * Halo Wars
 * Halo 3: ODST
 * Sadie's Story
 * Halo Legends
 * Homecoming
 * Origins
 * The Package
 * Halo: Blood Line
 * Halo: Fall of Reach
 * Boot Camp
 * Halo 2: Anniversary
 * Know Your Enemy
 * Halo Mythos
 * Halo Wars 2