# ACOG TA31RCO 4x32 {% hint style="info" %} Introduced in **0.2.414** {% endhint %} The TA31RCO is a 4x always-on optical sight that uses a combination of optical fiber and tritium for illumination.

Available in both the Army (M150 RCO) and USMC (M7 RCO, distinguishable by its metal instruction band and LaRue Tactical LT799 Mount) variants. Both can also be found fitted with the Anti Reflective Device (ARD).

The horseshoe reticle is sighted for 5,56 round and hits center at 100m. The top of the vertical line is sighted for 25m and 300m. Greater distances can be read off the vertical line. The horizontal lines can be used to estimate distances and measure target sight. The separation between large lines is 10 mils, with the small lines denoting the 5 mil. 1 mil corresponds to 1 m spacing at a distance of 1 km. In the image below you can see a 1 m cube being sighted at 100 m being exactly 10 mils.

1 Meter Wide Object at 100 Meters = 10 mils

The tritium ensures that the horseshoe and the top of the bullet drop scale are clearly visible in the dark.

Using the ARD significantly reduces the amount of light that enters the scope, effectively dimming the image (compare with previous).

ARD Dimming (Compare With Previous Image)

The army version of the sight, the M150 RCO, has a chevron reticle, the top of which is sighted at 100m. The rest of the markings are similar to the horseshoe.