Is it possible your rings are not correct for your rifle?
I know Ruger M77 have different height rings from front to back. If they were reversed, you would have serious problems with elevation.
What you describe does NOT sound normal.
It will be a job, but you might want to re-center your scope adjustments and check your crosshair with a laser bore sight. The kind of gross error you are describing sounds like a major problem with either the scope rings or the base.
Take your elevation knob and windage knob and turn them in one direction until they hit the stop. Don't force them.
Turn each of them in the opposite direction until you hit the stop and COUNT THE NUMBER OF TURNS. Again, don't force them.
Now take each of those adjustments and reverse direction again and turn them 1/2 number of the turns required to go from stop to stop.
For example if it takes 20 turns to go from stop to stop, the zero point is approximately 10 turns.
Use a laser bore sight or just look through the barrel at a target about 25 yards away.
Your crosshairs SHOULD be close. You should NOT be running out of adjustment to dial in the elevation.
Is it possible the base is not machined correctly or could you have some junk under the base?
I have a couple of Remington 700 and have not experienced that kind of major disconnect on either one.