I guess what is confusing me is looking at the exploded drawings of the M14 rear sight group and then looking at my M1A (Standard, purchased new in December).
The book said to loosen the screw on the elevation knob side enough so the wheel settings could be indexed with the 200 yrd zero. The screw itself is only about a 1/4 to 3/8 in long, and I couldn't loosen it enough without the sight moving on me. I ended up (inadvertently) removing the screw (where I found out how long it is...from the diagrams it looks like it should go all the way through). When the sight and wheel were set, I found that there is some rubber washer/sleeve inside the elevation wheel which prevents the short screw from being tightened easily. I feel that it tightened back into its hole enough, but the elevation wheel seems to move very easily, and will move during recoil (lowering the sight).
The book made it sound like this was an easy task, and while monkeying around with this screw (and tightening it) shouldn't cause the sight to move around on you. To tighten everything, I had to have the elevation wheel held in place, as well as the sight apeture.
-Zmeja