Why does my zero keep wandering?
Every time I go shooting my zero has wandered a few inches at 200 yards. The groups are always great (often 2" @ 200 yds, which is good for my bad eyes), but they keep wandering. I' ll re-adjust it a few clicks to dead on, but the next visit the group has moved.
This also happens on the same day when I readjust for 600 or 1,000 yards, then move the scope back to 200 yds afterwards. Temperature doesn' t seem to be a factor, so I' m wondering what' s causing this.
Here' s the set-up: Model 70 Classic Stainless in .300 Win Mag with BOSS at the factory setting. 2.5-8 Vari-X III. 180 gr Sierra ProHunters ahead of 75 gr of RL22 (2950-3000 fps). (The problem also occured when I was shooting 2850 fps with 70 gr of IMR 4831.)
I sent the scope back to Leupold, who found defective internals, which they said they replaced. The problem continued. I also switched out the factory plastic stock with a glass bedded HS Precision stock, but the problem remains.
Any suggestions where to go next? Sure would appreciate your input. (I still suspect the scope, but I' m not an expert at this stuff.) I' m spending a lot on bullets and powder!