by goalie on Mon Mar 30, 2009 6:20 pm
Disclaimer, I didn't read all the replies, so I apologize if I am spouting the obvious or previously stated:
Did you mount the scope yourself? If not, I would start by not just checking the rings/base screws for tightness, but I would remove them, clean the threads, and re-mount the scope myself. While the scope is un-mounted, I would check it for rattling or anything that appears loose or "off." Unfortunately, if what you describe is the scope, it is usually the reticle or other internals that are broken/loose/etc...and it is a factory-fix.
Also, for the sake of clarity, is the rifle having a wandering zero, where the group is moving 6-8 inches, or is it shooting each group like a crack head shot his Glock sideways from the 7 yard-line at Bills????
Also, look at the muzzle of your rifle after you shoot it. If you have a good-shooting custom rifle, you should have a symmetrical pattern of powder residue on the crown. If you don't, you might save yourself a lot of time and effort by dealing with a dinged crown before you go nuts trying to fix a scope that isn't broken.
What do you have for mounts? I have a few scopes that are known to hold zero and allow the shooter to shoot decent groups on Warne rings. Try and borrow a "proven" scope and shoot it on the rifle ASAP. It's the easiest way to rule out the rifle and confirm that it is your scope or mount that is the problem. You could also shoot another "proven" rifle with your scope to confirm the same.
It turns out that what you have is less important than what you do with it.