I picked up a used Leupold scope that had a set of Sako rings on it. One of the screws on one ring had a badly messed up slot and couldn't be removed by ordinary means. The person that sold me the scope said I would have to drill it out.
What worked great and only took a few minuted was cutting through the screw in the slot between the uppper and lower rings with an Exacto razor saw. I was carefull not to touch the scope and got the screw out without damaging the scope or the rings in a only a couple of minutes. Much faster and easier than drilling could ever be.
A very usefull trick to know if you ever run into the same situation and there is a thin gap between the two upper and lower ring halves as is common.