Beneath that is a mirror prism reticle with built in cross-hair drops etched in the high quality glass and appropriately spaced in 10-yard increments to 80 yards, with shorter, intermittent hash marks representing 5-yard increments.
The ACOG (Advanced Combat Optical Gunsight) crossbow reticle spacing is based on extensive testing with a range of crossbow-arrow combinations. The scope comes in three reticle options: XB1 for crossbows rated at 300-340 fps, XB2 for 340-400 fps, and the XB3 for 400-450 fps. Trijicon engineers recommend going with the lower range model for borderline speeds.
The upper portion of the glass is also etched with the Bad River ranging system, giving it built-in ranging capability. It creates a unique frame of reference with a single horizontal lower line (the 30-yard cross-hair) and a series of graduated upper steps notated with corresponding ranges, the distance between which is based on average size of deer and elk chest measurements. This allows a shooter to range, move to their holdover reticle and pull the trigger without lifting their head off the stock.
The ACOG requires no batteries. Fiber optic mounted on the scope housing gathers ambient light and transmits it to the prism for daytime illumination. It’s also fused to a tritium lamp—radioactive gas (approved for use by the NRC) sealed in a glass vial— that glows by itself for low-light conditions. With a 15-year half-life, the tritium will continue to provide ample light for the lifetime of most, if not all, shooters.
The glass and 7075-T6 forged, hard coat anodized aluminum housing and internal adjustments are designed to meet rigorous military specs, and it’s been drop-tested up to 2 meters. The ACOG weighs only 5.9 ounces and is made in the U.S.A. Trijicon has several mount options that will adapt to most any Picatinny or Weaver rail and fit most any crossbow on the market.