Sometimes it is better to leave things alone. It may be throwing curveballs, but they are all going in the same place. Now just shoot it until it is a smoothbore. That should only take about 10K rounds.
I also have a Remington 700 that has the holes drilled off center. You can see this one with it with your eyes, it is about 1/16" off center, I have had the rifle for 9 years so I don't think that Remington would do anything about it. It is a sendero in 7 mag. and will drive tacks. I had to put on the Leupold 2 peice bases, and I also would like to put on a Piccatiney on so I can switch scopes from my other rifles, so I appreciate the info on the base. Thanks