Scope adjustment windage POI vs MOA???

[CWM-RHG]

Hello everyone. Myself as well as several of my friends all have long range guns with Nightforce NXS scopes and Vortex. All of us have experienced the same thing many times. We all shoot consistent 1/4"-3/8" groups at 100 yds. We will shoot a tight 3 shot group with perfect elevation but say 3/4" away from center left or right. We will make a 3 click adjustment to correct the windage. We will now shoot a tight group 3/4" on the other side of center. For whatever reason, it moves the POI more than 3/4". Are we missing something here? Isn't 3 clicks 3/4" at 100yds? Help us out if you can. Maybe someone from Nightforce can explain. Thanks everyone..

 

[cross]

I have a Nightforce that does the same thing (NXS 2.5-10 x20mm). I've adjusted as necessary and lived with the results but am curious if anyone has an explanation for this.

 

[ShtrRdy]

There are two things I can think of at the moment that have affected me. One is if the distance from the muzzle to the targets is closer than what you think it is. The second is making the sight adjustment and then getting back in behind the rifle but your position is slightly different than before and the group ends up in a different place.