From 45ACPKing ...
Testing rear sights
Test the rear sight, turn it's windage knob and see if it is snug and the same tension through left to right range. Clicks should be positive and even throughout adjustment.
Next turn windage all the way to right side and then adjust elevation through its range, observe windage knob, it should not turn or move with elevation adjustment...if it does, this is the waning sign of a faulty windage lock collar.
Next look at the rear sight base itself, the vertical centerline should be machined center of the base, often its cut too far to the right of center.
Flash hider, have a good look at it, an out of spec front sight base will be noticeable if you look closely. It could be titled or off center. Rear sights are easily replaced with m1garand rear sights (M-14 Doc)
Rear sight problem?
Hold elevation knob firmly and insert slot screw driver into windage knob lock collar. Turn collar 1/2 turn, then try normal adjustment of sights. If this procedure fails to produce movement in the sights, my guess is the pinion shaft threads have been stripped and seized.
Sights that have been seized like this can be exceptionally difficult to remove for replacement.
To remove, windage must adjusted all the way to the left, then the lock collar can be loosened while holding windage knob itself from turning as you loosen the center collar.
Once loosened fully the windage knob should pull free with a few turns of the knob to the rear.
If the windage knob will not release, or if it was difficult to turn the center collar, the pinion shaft has been stripped by the collars lock ring.
Gentle use of a flat blade screw driver may be needed between receiver ear and windage knob to manipulate the knob as you turn it. This should be done with extreme care as you do not want to bend, crack or damage the windage ear of the receiver
Replace rear sight with an M1Garand, Springfield or genuine m14 rear sight
In many case one would only need to replace the elevation knob and pinion assembly and the windage knob.
To remove sights follow these steps:
When removing the rear sight can be a bit of a challenge getting it back together is more-so. To remove the Rear Sight, start by completely lowering the Rear Sight Aperture into the rear sight housing by turning the Elevation Knob.
With the Aperture bottomed out, use the Combo-Tool to loosen the screw on the Windage Knob (right hand knob) by turning it in a counter clockwise direction. Back this screw all the way off. It won't fall out but the threads must be completely disengaged. the screw on the Windage Knob (right hand side) is completely backed off - hold the Elevation Knob (left hand side) so that it will not move.
At this point turn the Windage Knob in a counter clockwise direction until it comes loose and can be pulled off. The Windage Knob is then removed from the Sight Assembly …with the Windage Knob removed the Elevation Knob can easily be pulled off of the Sight Assembly from the left.When both of the sight's knobs have been removed the next step is to remove the Aperture. Then pry up under sight cover until it springs loose.
To remove sights follow these steps:
First adjust windage all the way to the left as far as it will go.
Next, undo the windage lock sleeve with flat blade screw driver, turn until loose, do not try and remove, collar is held in with a retaining clip.
Next, with collar loose, undo the windage knob and remove the knob.
Remove elevation pinion by pulling out of sight base
Remove aperture
Insert flat blade screw driver into aperture area under sight cover and gently pry up until it springs loose.
Done.
Installation,
Clean and regrease all parts
Install sight base and rear cover together
Dab of grease to receiver at sight location recess
Use flat blade screw driver under back of sight base on bottom lip of sight cover and push firmly, sight cover should snap into place
Next, install aperture
Next install elevation pinion, ensuring it is completely in and meshed with aperture.
Slide sight base to the left side
Install windage knob and hold with your thumb, turn the lock collar only in a reverse direction until you feel it sink in a bit it has now engaged the pinion shaft correctly
Next turn the collar with screw driver forward until it comes just snug
Then turn windage knob to engage with sight base
Adjust lock collar as needed to tighten or loosen the sight knobs
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Web site with pics and info for rear sight removal…below
http://www.civilianmarksmanship.com/striphtml/detailstripsight3.html
http://www.youtube.com/watch?v=AoK9Zxk38_U&feature=player_embedded