My rear sight elevation keeps moving down (bottoming out from 10 clicks up) after 2 clips. The screw seems to be in tight. What should I inspect next, and if I need a replacement part, which one would it be?
You need one of two parts, either the gears are worn on the apeture assembly, or the pinion assembly. The most likely culprit is the pinion, as they are of softer metal than the apeture. Try CMP fo parts first, if they dont have it, try Sarco or Numrich. Hope this helps.