Read that article by Jack O'Connor many years ago sighting in at 25 yds dead center and being 3'high at 100....have being doing it for 40 years like that and about every caliber you pick up will be like that .Look at JBM Ballistics and zero your given gun at 25 yds and look at where it will be at 100.....about every time it will be 3" high at 100. I was looking at this few days ago with a 308 shooting a 130 grain TTSX at about 3165 fps and at 100 it was 3.1" high. What is happening is dead center at 25 bullet starts to rise, and at 50 yds will be like 1/2" inch high and still rising at 100. I always like a 3" high at 100 so that at 300 yds you do not have to hold high....will only be 1 to 3 inches low for most calibers. Even at 200 yards bullet still rising.
