bigalexe.
well, the M14 is a battle riffle and when designed, didnt have optic mounting friendly ergonomics. these guns have always had issues with holding their zero when scopes are mounted (traditionaly on top of the receiver). i have the bassett mount which has proved well however. also, when mounting near the rear, it raises your sight picture and the stock was designed for a low profile of aim (iron sights).....so you need to modify your stock by putting a cheek pad on there.
the reason i put the aimpoint up front is so it sits low (not having to add a cheek pad) and i can co-witness with my irons if my battery dies on the aimpoint.