Zeroing with camera based reticles

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Zeroing with camera based reticles

Post by phoenix » 26 Apr 2014, 13:35

This one's for users of scopeless set ups which rely on the camera privacy zones for a reticle.

One of the most common methods of zeroing a normal scope is to fire 3 shots at a target and then, assuming a reasonable grouping, and without moving the rifle, adjust the elevation and windage knobs on the scope so that the reticle is positioned over the point of impact of the group.
This works well if the rifle can be clamped so that it doesn't move.
If the rifle moves, you pretty much have to start all over again - which, on a centrefire can get expensive

On a scopeless set up where the camera generates the reticle, the process can be made somewhat easier by expanding the reticle lines into rectangles with one edge of the rectangle on the original point of aim and the new edge of the rectangle on the point of impact.
By doing this you can always get the rifle onto the original point of aim and make adjustments to the width and height of the rectangles until the opposite edges of the rectangles form a corner which lies on the point of impact.
Hopefully this sketch will make it clearer
The top sketch is the situation after taking 3 shots with the reticle on the point of aim - obviously the point of aim needs to be adjusted up and to the left
The middle sketch shows the lines expanded into rectangles with the original POA at the lower right junction of the rectangles and the new POA at the upper left junction of the rectangles. Even if the gun moves during this process, the original POA is still there, so the gun can be accurately re-positioned to allow the new POA to be set
The lower sketch shows the final position of the reticle with the rectangles having been shrunk back to single lines which meet at the new POA - which, hopefully should also be the POI