Correct 25, 100 200

THIS . Seen it happen a lot.

Sort of like a double rifle, they are regulated to a specific range, in your case 100 yards. Like others have mentioned if it's off to the right at 200, back up to fifty and see if it's a little left.

scope mounted crooked, could be how the rings are tightened on the base, could be the action drilled crooked. If its off 7.5 moa at 200, it should also shoot 3.75 inches left at 50. If the scope is that crooked you should be able to see it just by looking.

I don't bet but if I did, I would put money on the scope being the culprit.

WS

Sounds scopey to me…… but. All these guys who can put 5 rounds in a clover leaf, and not one mention of wind?…..lol. The one factor you can’t accurately predict along the flight path. 200 ain’t much, but still.

would take approx. a 60 mph wind to drift 12" at 200 yards.

Think about that. Then renter the numbers……lol
You be missing my point though. At this distance it’s probably irrelevant, but nobody asked what the conditions were….. That’s a bit of a factor.

Theres your answer.

Get rid of the Bush

When shooting OK at 100 yards, move to 200 yard target, but don't touch the scope settings. If impacts stays centered, not the scope. If group moves sideways.......scope has mounting problem.

1) You were on at 100, off at 200, and still on at 100 when you rechecked. That eliminates the ammo or a broke or loose scope.

2) No change of magnification so not that.

3) 7.5 15 inches in 100 yds is too far off to be wind, rest, or shooter in any reasonable situation.

4) You said the old scope was accurate at 200, but not if both 100 and 200.

It sounds like a scope mounted off centerline as GCP said. Scope and barrel centerlines only intersect at one distance. If the old scope was on at 100 AND 200, it's not off centerline screw holes but probably a base or ring problem.

Or your dead on at 100 is not dead on. Or wind

So did you try a different optical yet?