p.s. The Redfield windage marks are a convenience and a reference point. It is not unusual for an adjusted sight to be off-set from the center mark on the staff. Probably more significant (in revealing problems) is how the peep location lines up with the centerline of the barrel, when viewing the front sight.
p.p.s. With the Redfield #102-K, you loosen the left screw and then tighten the right screw to drift the aperture (and shot group) to the left. Hopefully, you don't run out of adjustment.
