How do I co-witness / align the rangefinder with my riflescope?
A: There are 3 ways to accomplish this:
1. Simple method
Point scope crosshairs at a target at the approximate distance you intend to shoot. Stabilize shooting platform so the scope doesn’t move. Use the windage and elevation knobs on the mount to point the rangefinder reticle at the same aiming point as the scope reticle. Re-verify scope reticle has not moved from the target. Verify rangefinder reticle matches aiming point of scope. For extra accuracy, measure the distance between center of scope occular lens and the center of rangefinder occular lens, and maintain rangefinder point-of-aim parallel to scope crosshairs to prevent point-of-aim divergence over large distances.
2. More accurate method
A more accurate method is to have a target at the approximate distance you intend to shoot, where you have a much longer distance behind the target to use as a contrast. Point scope at the edge of the target. Adjust rangefinder so that it detects the point at which aiming point goes off the edge of the target both horizontally and vertically. Fire rangefinder while moving off the edge of the target. The rangefinder should be aligned so that it switches to displaying the much longer distance behind the target just as scope crosshairs move off the edge of the target. Again, for extra accuracy, measure the distance between center of scope occular lens and the center of rangefinder occular lens, and maintain rangefinder point-of-aim parallel to scope crosshairs to prevent point-of-aim divergence over large distances.
3. Most accurate method – requires digital night vision clip-on like the PARD NV007
Third method is to use a clip-on digital night vision scope like a PARD NV007 or the cheaper “DIY” Night Vision scopes priced around $100. Digital night vision shows the infrared spectrum used by the rangefinder, so the laser from the rangefinder becomes visible flashing on the target. This makes windage and elevation adjustment for the rangefinder easy and precise. Again, for extra accuracy, measure the distance between center of scope occular lens and the center of rangefinder occular lens, and maintain rangefinder point-of-aim parallel to scope crosshairs to prevent point-of-aim divergence over large distances.