I would agree in putting up with the loss of the mounts if they are replacable. However, I wouldn't drill them out unless I had a carbide drill of the correct dia. I don't know about American socket headed cap screws, but here in England they are as hard as the hobbs of hell.

Better just to saw the mounts through on the inside of the screw. If your not happy sawing freehand with a hacksaw then set the item up in a vertical mill and use a slitting saw instead. You only need to cut through the top half of each mount then just lift the scope off.

Harry

Biology is the only science where multiplication can be achieved by division.