What scope, rifle and mounts? what you described if I m thinking right can happen if you run out of travel on a scope with not enough adjustment range for the mounts
Are you near the end of travel one direction or the other? it has been a while but remember one scope that was and ran it all the way the other direction, then back to the middle and started over sighting it in and that time things worked. Don't even remember what scope it was
It's a Thompson Center Dimension with a Nikon Prostaff 4 - 12 X 40 scope, and AccuShot Picatinny/Weaver Medium Profile 2-piece 1-inch Rings for mounts. Not sure about the end of travel.
Are the groups moving right/left instead?
Honestly haven't messed with right or left once I got it directly above my target.
Also, possible user error. This is my first rifle to sight in.
Thanks for the help