this problem I have run across makes no sense to me the setup is a cooper 54 Excalibur in 6.5cm nightforce nxs 5.5-22x50 new rifle for me.i have been struggling with this rifle trying to get decent groups tried 5 different types of factory ammo getting consistent 1.25 inch groups with most of them not as good as I expected so as I was working with it the other day while I was giving the barrell cooling time I got out my 7lb 300 win mag it has a vx62-12 & shot sub 1/2 in group with factory rem 180 cl it got me thinking so the next groups I shot with the 6.5 I took the magnification down from 22x to 12x & just like that went to 1/2-3/4 in groups with all the 6.5 ammo I have no idea whatsoever what could cause this maybe somebody here can enlighten me as to the cause