S&W rear sight

I was adjusting rear sight for a new load for the M-14 and couldn"t count or feel the clicks on elevation. It felt like only 1 click for entire revolution, I'm sure there are 6. I've never taken these sights apart, and it probably only needs a small part to fix it. I could use some help on this one.
  Stan

https://youtu.be/uJRUUIpwLa8

If I recall,  there's a tiny, and I mean tiny, detent and spring inside the head of the screw. I guess I should say nut, the slotted part that you turn with a screwdriver is actually the nut. When you back it out, the detent goes flying across the room, so maybe disassemble it in a large ziploc bag or something.  I would try spraying it with some kroil first and see if that frees it up.

Brownells sells a repair kit and tool. You can make your own tool from a small cheap flat blade screwdriver and a Dremel.

Thanks guys. I'll load it up with some kroil, then check it in the morning.
Stan