|Faction|| - NATO|
|Zeroing range|| Standard variants:
|Variants||ACO (Red), ACO SMG (Red), ACO (Green), ACO SMG (Green)|
The ACO (full name: Advanced Collimator Optics) is a collimator sight used by all 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.
In addition, dedicated SMG variants exist for both counterparts but have reduced zeroing ranges (100 m) for use on submachine guns and other short-ranged firearms. These are also unable to have their zeroing changed.
- ACO (Red): Uses a red-tinted bullseye reticle.
- ACO SMG (Red): Uses a red star reticle.
- ACO (Green): Functionally identical to the standard red variant but has a green chevron-dot reticle instead.
- ACO SMG (Green): 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.
Optical sights of comparable role and configuration
|Weapon attachments of ArmA 3|
|Collimators||ACO • MRD • Yorris J2|
|Holographic sights||Mk17 Holosight|
|Riflescopes||ARCO • ERCO • MRCO • RCO|
|Sniper scopes||AMS • DMS • Kahlia • LRPS • MOS|
|Thermal/Night vision||TWS (MG) • Nightstalker • NVS|
|Aiming devices||IR laser pointer|
|Suppressors||Sound 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)|
|(Parenthesis) denote variants. | Marksmen DLC | Apex DLC ||