Most mounts attach rails. You need rails designed for the M-14 that drop into the divots for Ruger scope rings. Warne, I think made mine.
The mount itself should also be made for the M-14 as most others are for ARs and mount the red dot way high to accomodate the carrying handle/sight that is not part of the Mni - 14 design.
I got a mouint made specifcally for my AIM Point red dot by the manufacturer. Works perfectly.
Good luck,
wunbe