Test the rear sight, turn it's windage knob and see if it is snug and the same tension throught left to right range. Clicks should be positive and even thoughout adjustment.
Next turn windage all the way to right side and then adjust elevation through it's 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 it's 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 and flash hiders and rear sight parts can be ordered through brownells
