Armed Assault Wiki
Faction Icon-side-blufor.png NATO
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Icon-side-redfor.png Gendarmerie
Icon-side-redfor.png Russian Spetsnaz
Icon-side-greenfor.png AAF
Icon-side-greenfor.png LDF
Icon-side-greenfor.png L'Ensemble
Type Collimator
Magnification None
Zeroing range Standard variants:
  • 200 m (fixed)

SMG variants:

  • 100 m (fixed)
Variants Red, SMG (Red), Green, SMG (Green)

The ACO (full name: Advanced Collimator Optics) is a collimator sight used by several BLUFOR, REDFOR and INDFOR factions in ArmA 3.


The ACO features either a red-tinted bullseye or green chevron-dot reticle.

Both variants have their zeroing fixed to a range of 200 m by default and cannot be adjusted.

Dedicated SMG variants also exist for both counterparts but have reduced zeroing ranges (100 m) and are meant for use on submachine guns and other short-ranged firearms.

Like with regular ACOs, the SMG variants also cannot have their zeroing adjusted.


Uses a red-tinted bullseye reticle.

Uses a red star reticle.

Functionally identical to the standard red variant but has a green chevron-dot reticle instead.

Functionally identical to the red SMG variant but has a green T-Dot reticle instead.


  • The ACO appears to be based on the "Railway" series of red dot sights manufactured by C-MORE Systems.
  • It is the most ubiquitous optic in ArmA 3, as almost every military and non-state actor group utilises either (or both) the standard and SMG variants.
  • A unique Defunct variant exists exclusively for use in the First Contact campaign which features an ACO with its reticle disabled. Functionally however, it remains identical to regular ACO (Red) sights.


External links

See also

Optical sights of comparable role and configuration

Weapon attachments of ArmA 3
Collimators ACOMRDYorris J2
Holographic sights Mk17 Holosight
Sniper scopes AMSDMSKahliaLRPSMOS
Thermal/Night vision TWS (MG) • NightstalkerNVS
Aiming devices IR laser pointer
Illumination Flashlight
Muzzle SIMCOM AdapterSound Suppressor (5.56 mm, 5.7 mm, 5.8 mm, 6.5 mm, Stealth, 7.62 mm, .338, 9 mm, 9.3 mm, .45 ACP)
Weapon mounts Bipod
(Parenthesis) denote variants.
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