at 500 I was hitting about 3.5 inches low so I'm going to start at 500 when I go again and adjust my dope . It just got dark on us before I got it right. 800 is going to be tricky with a 12x scope I'm guessing.
So you were .2 MIL low, remove inches from your thinking.
Paint your targets white before shooting them. It is much easier to see the target as well as see where on the target the bullet impacted, so that you can make the correction. In other words, a white target at 500 that you did hit, but are low, measure it with the reticle. Hold the reticle on the center of the target and see if it is .1 low or .2 low, or .3 low. Say it is .2 low, turn the elevation turret "impact up" .2, shoot again. With white targets that works at any distance. When I have guys come to my range I make sure the targets are freshly painted the day before. We never go down range to inspect the targets, because we can see the black dot the bullet made inside the white field.