Editing M99 Stanchion

{{Era|UNSC|HCW|Post}}

{{Weapon

| manufacturer=

| length= (o/a): {{Convert|68.90|in|cm}}

| weight= {{Convert|20.0|kg|lb}}

| feed=10 rounds

| ammotype=5.4mm/.21 caliber

| velocity=15,000 meters/second (9.3 miles/second)

| range= {{Convert|4.5|km|mi}}<ref name="HGN122"/>

The '''M99 Special Application Scoped Rifle''', also referred to as the '''M99 Stanchion Gauss rifle''' or simply the '''Stanchion''', is a [[United Nations Space Command]] anti-matériel rifle.<ref name="HGN122">'''Halo Graphic Novel''', ''Page 122''</ref><ref name="CH">'''Halo: Contact Harvest''', ''page 16''</ref>

The M99 works on the same operational principles as other magnetic weapons such as [[mass driver]]s and [[Magnetic Accelerator Cannon]]s, albeit on a much smaller scale. This system works through using a series of electromagnetic coils (an asynchronous linear induction motor) rather than chemical propellants as a source of kinetic energy. The M99's weight and bulk limit the weapon's use to highly specialized long-range precision sniping roles.<ref>[https://www.halowaypoint.com/en-us/universe/weapons/railgun '''Halo Waypoint''': ''Railgun'']</ref>

The M99 can be used with a [[portable computer]] to provide the ballistic calculations necessary to engage long range targets. The rifle can also be integrated with other systems, such as [[ARGUS drone]]s for trajectory and ballistic data. The M99 also uses the [[ATLAS+]] system developed by [[Ohana Prescient Systems]].<ref name="HGN122" />

The 5.4mm/.21 caliber round is very small in comparison to most standard firearms of the era, but using the Gauss technology, the small rounds have the ability to rip targets apart, even through office buildings.<ref name="CHP"/> This is due to the high force imparted on the round via the Gauss acceleration method. The round creates shockwaves as it passes through the target. In the case of material targets, this is a minor explosion and the creation of structural fractures. In the case of personnel targets, it simultaneously rips apart and pulverizes the body around the impact area. Even hits in an extremity or near-misses can be deadly.

The M99 Special Application Scoped Rifle entered production in [[2491]].<ref name="HGN122" /> Production was ceased in [[2521]].<ref name="HGN122" /> Though it was used mainly for anti-matériel operations, the .21 caliber round (with a muzzle velocity of 15,000 meters per second) proved very effective against "soft" targets such as personnel.<ref name="CHP">'''Halo: Contact Harvest''', ''Prologue''</ref>

In [[2502|March 2502]], then-[[Corporal]] [[Avery Johnson]] used an M99 Stanchion to [[Operation: KALEIDOSCOPE|assassinate]] [[Jerald Ander]], the leader of the [[Secessionist Union]] cell on [[Harvest]]. Johnson took the shot as the terrorist leader was driven by in an open-topped truck; Ander's head and upper torso were severed by the impact.<ref name="HGN122"/> In [[2524]] during [[Operation: TREBUCHET]], Johnson used a Stanchion to kill an [[Insurrectionist]] terrorist driving a bomb-rigged truck; his first target was torn apart by the impact force. However, Johnson's second target detonated a bomb inside a [[Jim Dandy]] restaurant, killing herself, three [[UNSC Special Forces#Naval Special Warfare|Special Warfare]] Marines, and 38 civilians.<ref name="CH"/><ref>'''Halo: Contact Harvest''', ''page 86''</ref> Early on during the [[Human-Covenant War]] in March [[2526]] [[Blue Team]], [[Gold Team]], and [[Green Team]] utilized M99 Stanchions during an attempt to capture the [[Covenant frigate]] ''[[Radiant Arrow]]''.<ref name="HSS2">'''[[Halo: Silent Storm]]''', ''Chapter 2''</ref>

Shortly after the [[Subjugation of Earth]] [[Spartan-IV]] [[Kojo Agu]] used an M99 Stanchion given to him by the [[United Rebel Front]] while on [[Cassidy III]] to destroy the [[data pad]] that the [[Created]] [[Smart AI]] [[Leonidas]] was stored in. Production of the rifle had since ceased and Agu considered the weapon to be "old-school." <ref name="HBB">'''[[Halo: Bad Blood]]'''</ref> [[Snipers]] assigned to the {{UNSCShip|Spirit of Fire}} continued to use the Stanchion as late as April [[2559]], as the ship had been lost in space for [[2531#Febuary|the past 28 years]].<ref>'''[[Halo Wars 2]]'''</ref>

*'''[[M99A2S3 Stanchion]]''': The M99A2S3 is a variant of the M99 created by [[Isabel]].<ref>[https://twitter.com/JeremyCook3D/status/950541458829844480 '''Twitter''' ''- Jeremy Cook M99A2S3 breakdown'']</ref> It has an inertia buffer that helps manage recoil.<ref>[https://twitter.com/JeremyCook3D/status/950592593376628741 '''Twitter''' ''- Jeremy Cook on the inertia buffer'']</ref>

*Using the following formula: ''K = m(v*v)/2'', a round with 30.757MJ of muzzle energy and a muzzle velocity of 15km/s would have a mass of 271.78 grams or .6lbs. This apparent discrepancy can be accounted for in one or both of the following ways:

**It can be assumed that the weapon is not normally fired at its highest-rated output, as repeated firings could lead to barrel deformation due to both the electromagnetic repulsion and friction-induced heat of the projectile traveling the length of the barrel. Even if fired at 75% of full output, a round will still overpenetrate obstacles and inflict catastrophic damage to soft targets.

**The 5.4mm designation refers to the ''diameter'' of the round, not its length. With this in mind, it is likely that the round is significantly longer than it is wide & is composed of a super-heavy alloy such as depleted uranium, in order to further enhance its destructive potential by concentrating more mass in a smaller area, which would allow more kinetic energy to be delivered to the target.

<references/>