You just found out why some people choose to bore sight their newly scoped rifles (centerfire or muzzleloader), it would've saved you from shooting $10 worth of PowerBelts into the dirt.

When I recently scoped my inline, I set up a target of 20"x30" paper at 10 yards and when I walked 'em into bullseye, I could then move back to 25, 50 then 100 yards to tweak the scope adjustment using loads that grouped the best.