M99A2S3 Stanchion

From Halopedia, the Halo wiki

M99A2S3 Special Application Scoped Rifle
M99 Stanchion.png
Production overview


Model series:

M99 Series[2]


Recoilless anti-matériel rifle[2]



208.7 centimeters (82.2 in)[4]

Ammunition type:

APFSDS rounds[3]


7 rounds[3]




Smart-link compatable ATLAS HISHOT PRO-X scope[2]

Service history

In service:

Post-Covenant War conflicts[2]


The M99A2S3 Special Application Scoped Rifle is a weapon in the M99 Stanchion series of high-powered anti-materiel rifles in the service of the United Nations Space Command.[2]


Artwork of Lance Corporal Sparks.
An M99A2S3 Stanchion in use by Devon Sparks, the sniper for Sunray 1-1.

Design details[edit]

The Stanchion is built on a frame similar to that of the SRS99-AM sniper rifle. Unlike the SRS99, however, the Stanchion is a coilgun, and has more in common with Gauss cannons and larger naval guns in terms of operation than a regular firearm. The weapon is powered by an Asychronous Linear Induction Motor (ALIM), capable of accelerating its munitions to several thousand metres per second.[5] Accordingly, the receiver and barrel of the Stanchion are much bulkier than a conventional sniper rifle, with a protective housing visually reminiscent of the ARC-920 railgun. The Stanchion is renowned for overpenetration and collateral damage, making it extremely effective against its targets. The high muzzle velocity of the weapon makes it extremely powerful and accurate at long distances.[5]

Midway down the barrel, the M99A2S3 is located with an inertia buffer designed to help lessen the recoil produced when firing the weapon.[6] The fore of the rifle features a bipod that can be folded back and secured on the weapon. The rifle is compatible with an ATLAS HISHOT PRO-X optic, capable of being smart-linked with an operator's heads-up display.[2][3]

Unlike the standard M99 Stanchion rifle, the M99A2S3 does not appear to require an external generator to power the weapon. As such, this leaves the operator free to move around the battlefield rather than stay anchored to one shooting location. Likewise, the M99A2S3 does not appear to require the use of an external targeting computer.[7]


The Stanchion fires tungsten penetrator darts, with a muzzle velocity of several thousand metres per second.[5] The darts are stored in a disposable burn-up casing that contains a sabot and the dart itself. The weapon's detachable box magazine is capable of holding 7 rounds before a reload is required.[3]

Development history[edit]

Developed and manufactured by HRN,[1] M99A2S3 Stanchions are also capable of being manufactured aboard the Phoenix-class colony ship's internal factory modules. In 2558, the Smart AI Isabel created a design template for the weapon on the Ark, given the code "ISABEL-2558-01-00023". This design template was later put to manufacture following the arrival of UNSC Spirit of Fire to the installation in 2559, with Stanchions built in manufacturing block 23-CELL-14.[3]

Screenshot of an Ardent-clad Spartan in Halo Infinite used to represent August-099 on Arcadia during the events of Halo: Hippocratica.
August-099 wielding an M99A2S3 Stanchion.


During the Second Ark Conflict, the M99A2S3 Stanchion was used by Lance Corporal Devon Sparks of Sunray 1-1, and had achieved at least 17 kills with it. Sparks also customized his weapon with tally marks for every kill, a Dazzle camo pattern, and two charms; a Scorpio charm and an ODST Talisman.[2] During a mission on Arcadia in 2560, August-099 of Omega Team was equipped with an M99A2S3 Stanchion.[8]

In-game information[edit]

Halo Wars 2[edit]

The Stanchion features in Halo Wars 2 as a weapon that can be equipped by UNSC Sniper units. By default, snipers in Halo Wars 2 do not equip Stanchions by default but instead use integrally-suppressed anti-materiel rifles more in line with a conventional ballistic rifle. The Stanchion sniper rifle is the second upgrade available for the Snipers and can be purchased for a cost of Supplies 0, Power 750.

The M99A2S3 Stanchion rifle is used in the Operation: SPEARBREAKER expansion for Halo Wars 2 as a unique weapon equipped by Devon Sparks, the sniper of Sunray 1-1. Sunray 1-1 (and by extension, the Stanchion) only feature in the levels Gatecrashers and Not on My Watch.

Halo Infinite[edit]

The M99A2S3 Stanchion is useable in Halo Infinite as a cosmetic weapon model introduced in Content Update 29. The weapon can be applied as a cosmetic appearance for the SRS99-S7 AM sniper rifle, and features no gameplay/mechanical changes.

Weapon Model Manufacturer Lore Rarity Unlock Requirements
Icon of the M99A2S3 Stanchion weapon model.
M99A2S3 Stanchion
UNSC "Traveling at fifteen thousand meters per second, the round whistled over the highway and hit the target at the apex of his sternum. The man flew to pieces as the round buried itself in a rooster tail of pulverized asphalt."

-- Halo: Contact Harvest
Legendary Purchase "Stanchion" Bundle from the Shop for 1,800 cR


List of appearances[edit]


  1. ^ a b Twitter, Halo (@Halo): ""Manufacturer: HRN" (From the video within the tweet.)" (Retrieved on Feb 25, 2024) [archive]
  2. ^ a b c d e f g h Halo Waypoint, Canon Fodder - Sweet Centennial (Retrieved on Sep 24, 2021) [archive]
  3. ^ a b c d e f Twitter, Jeremy Cook (@JeremyCook3D): "Ok, I made some orthos of the Stanchion for ya today." (Retrieved on Jan 30, 2024) [archive]
  4. ^ Twitter, Jeremy Cook (@JeremyCook3D): "we come up with 208.7 cm for stanchion." (Retrieved on Jan 30, 2024) [archive]
  5. ^ a b c d Halo Encyclopedia (2022 edition), page 171
  6. ^ Twitter, Jeremy Cook (@JeremyCook3D): "Think hightec recoil management." (Retrieved on Jan 30, 2024) [archive]
  7. ^ Halo Wars 2, Sunary 1-1 in-game unit
  8. ^ Halo: Hippocratica