@ 08:25 am (GMT)
Nathan FosterHi Tony, OK, it may be that the finish on the action was rough and that it has been buffed down a bit too much at the rear before blasting. Seems quite a large error though.
Also check that that nothing is pinched. Yours will have the mag box attached to the floor plate and should not pinch up like others, but do check that everything fits smoothly in the stock and that the barrel is floated. Check that the knox section of the barrel (start) is not being forced up, not just the forend tip.
Check also the scope screws. Fit them one at a time starting at the front. Fit the first, then wriggle the base. If the base wriggles, then the screw is impacting the barrel shank and will be affecting harmonics. Fit the second and check for protrusion. If its protruding, it will kick the upper bolt lug down and put it off center. Check for scratches on the lug. Then check the other screws for protrusion. If all is well, fit and re-bore sight.
Generally, the bore sight (using the bore as an actual aperture) should give you some info. If the bore sight goes well but the rifle then displays a major disparity, then there is some kind of harmonic / stress fault as per the examples given. Alternatively, if the bore sight goes poorly and things are out of whack, then we can look to the action finish or rail itself. To others- I believe it is important to actually eyeball the bore in this manner and become accustomed with bore sighting (provided the action design allows for it). Becoming reliant on lasers etc weakens your problem solving skills if you become reliant on them. Many aids are much the same, anyway, best to not get sidetracked down that path.
The turrets on the Nikon have a set range. Its hard for them to be out by a large margin. Such a problem would be rare unless there is a burr or some such interference making it feel like the thread stops halfway down. But this situation is a bit different.
It may be that you have to shim but in this case, I believe you would need two shims of either brass or ali, laminated with epoxy. Do take note that you can gain another 20 MOA using Burris rings.
If the rifle has a brake, take it off for now and work with the bare barrel, just in case gases are kicking things around.
Also, keep in mind that from here, I can only try and guess factors. I could be wrong about any or all of this. It may be something entirely different that I have not thought of. In any case, I hope this gives you some go forwards.