I found that my rifle drops differently than the computer programs. I shot a target aiming at the same point at 200 yds, 300 yds and 400 yds. I then measured the distance my groups dropped from my zero which was 200 yds. The 300 yd. group dropped 8"(comp. program said it should be 7"). At 400 yds the computer said it should drop 18.5", but the real drop was 21.5". This could have been my entering incorrect info into the program. BUT by me shooting the actual drops allowed me to have the correct arc my bullets take while going down range out of MY rifle.
With this info I had Vortex manipulate the computer program to give me the correct arc the bullet will take. The custom turret they made for me has been dead nuts accurate at every range. I proved this to myself while in Wyoming shooting on a 2,000 yd. range. I could not shoot that far, but was able to hit the gongs out to 900 yds on the centerlines. Wind moved the impacts left & right, but the hits were centered. My turret only goes to 900 yds. The caliber is 6mm Norma BR. shooting Berger 105 gr. VLDs.