Right Left Group shift when moving flip sight LR to SR

[albert]

Anyone have this problem? My smith and Wesson group moves about 3" to right.

[bonnie]

Not knowing what rear sight you are using and barrel length.

A windage (lateral) shift, when switching an A2 type rear sight from small to large aperture, will occur if the apertures holes are on the same plane, then rotated on the windage screw threads. This POI shift is magnified using a shorter barrel. Some makers compensate for this by having the large aperture on a slightly offset plane.

This is a replacement aperture that is compensated for this lateral shift.
http://www.blackhawk.com/Products/Stocks-Long-Gun-Accessories/Long-Gun-Accessories/On-Gun-Components/Sights/AR-15-M16-Same-Plane-Sight-Aperture.aspx

[albert]

Thanks Bonnie. I see that midway carries them. I'm really surprised that this wasn't ever an issue with the army. BTW my ar is a S&W.