If you've ever taken your elevation or windage to the extreme and tried cranking the magnification, there's a chance you've been scraping the erector (inner tube) against the inside of the scope's main tube.
Now would be a good time to move that inner tube to the center of the outer tube, take the pressure off the walls, and re-zero from there.
For internally-adjusted scopes, the process is pretty much the same.
1. Walk the scope up (elevation) and to the right (windage), taking the pressure off the internal spring. Keep going until you've hit the limit on both, stepping each a few MOA at a time to avoid damaging the erector unit.
2. Now, look up or estimate the total amount of travel each of those turrets will have. Divide that number in half.
3. Dial the elevation and windage down to that halfway value, stepping each one a bit at a time - like putting a car tire back on.
4. Done! Check to sure the power ring is not sticking and then go re-zero your scope.
For example, one of the scopes has a total adjustment of 50 MOA on the elevation and windage. The middle would be 25 MOA. Move the windage all the way right and the elevation all the way up.
Then work the adjustments down and to the left, 5 or so MOA at a time. Once you've gone down 25 and left 25, you should have the erector unit (inner tube) floating in the middle of the outer tube (scope body). You should have your full range of adjustment back, and this provides a good baseline to re-zero from. Plus, it tends to free up stuck magnification rings.