The Angle Cosine Indicator (ACI) is an indispensable sniper tool for long distance precision shots when aiming up-or downhill. The ACI helps you to easily calculate and correct the gravity‘s effect on your bullet‘s trajectory.

The bubble level enables the shooter to understand if the gun is completely level.

Our ERA-TAC-mount with ACI and bubble level can be easily attached to our UNIVERSAL interface. It is not necessary to alter the position of the scope. The position of the ACI is such that the red needle is visible even when using a scope with the illumination control on the left side and while already aiming. The position of the elevation turret remains always visible because of the lateral bubble level.

How to use the ACI 

1. Measure the distance to target by your rangefinder or your scope‘s reticle

2. Aim at the target and read the number shown on the Angle Cosine Indicator; multiply the actual distance by the shown cosine number to get the adjusted distance for gravity.

Example

target distance = 800 m

Cosine number shown on ACI while aiming at target : 0.87

800 x 0.87 = 696 m (adjusted distance to target)