Centered at 25 yards
OK, two possible meanings, here:
1. Your scope was *centered* meaning it shot to point-of-aim, regardless of where the internal settings were,
2. your scope was at its settings center and you were on paper, if not on target, at 25 yds.
What I'm saying boils down to:
1. if the scope had to be adjusted close to the end of its elevation or windage travel, just to get on the paper at 25 yds, I can see how 100 yds ( I would've tried 50 & 75, in any case) could be a problem, or
2. if your scope was centered in its settings and you couldn't walk your target out to 100yds, there's a problem with the mounting, the scope, or the rifle. How does it do with iron sights, if any?
Learning the hard way, I now try to mount a scope so that it's real close to point-of-aim with the settings centered (or at *midpoint*, if that lessens the ambiguity). This way, I have a lot of leeway for adjustments 360*.
BTW, as a scope gets close to its travel limits, it will also decrease the range on the other axis. A scope adjusted to the end of its vertical axis will have no windage flexibility.
HTH,
MR2.