Thread: Nikon monarch scope issue

Im using a nikon monarch 4-16x50sf on my tikka 300wsm on talleys rings. And it has been awesome for a couple of years. Never needed sighted or adjusted(only when I changed ammo) but with my latest load, I needed to adjust 4" down and 4" left. I adjusted it 4 moa on each dial(16 1/4" clicks.) She went left spot on. But went down twice as far. And its moving 1/2" clicks up and down now. What would cause this? I did think my shooting for a start. But consistant 4 shot groups are 1/2" so I dont think so?