ACOG (5.56mm Chevron/BDC Reticle)
ACOG optics are one of the most commonly used sights available to TAU-44 operatives, with many - including the unit's commander, Jansen - claiming that they are the best all-around optics. They offer an operator the ability to quickly and effectively engage at close, medium, and long range, thanks to its Bullet Drop Compensating (BDC) and ranging reticle.
Operators should be aware, however, that as almost all ACOG BDC reticles are configured for standard 5.56mm M855A1/EPR ammunition, this functionality will be less useful if you use different ammunition sizes.
While the BDC/ranging lines on the ACOG are relatively self-explanatory, the range-finding ability of the ACOG is often not fully understood by people. Each line and element of the ACOG chevron/BDC is sized and scaled specifically. At 300 metres, the base of the chevron is roughly equal to the width of an adult human, measured at the shoulders. Moving down the reticle, the same remains true for the lines at 400, 500, 600, 700, and 800 metres. This allows you to quickly compare the reticle to an enemy combatant at shoulder level and approximate the range of the target.
(ingame reticles may not match the illustration)
The below-pictured examples display the M150 RCO sights, demonstrating a reticle with three different shades of red which get darker as it proceeds down the BDC. This is a loose representation of the muzzle velocity decrease of standard 5.56mm M855A1/EPR ammunition over the distances marked. Up to 400 metres, M855A1 does not lose much power or speed. At 500-600 metres it begins to lose energy exponentially, and at 700-800 metres the bullet has lost much of its power and drops significantly (which can be observed by the much larger gap between BDC marks at this range). Other 5.56mm types should experience approximately similar drop as M855A1, with slight variations.