Sighting in varizone

[JB2010]

I had some scope issues a week or so ago. I got a new one sent to me from Excal. When I got it I sighted it in at 20-50 yards. I had the speed ring set on the 3 in the 350. The one I had before was set on the last zero in 300. I didnt figure that was that big of a deal. I was hitting fine with it and was using the exact same set up. Saturday morning before I went hunting I got it out and did a little shooting to build confidence before going to the woods. 20-30 was dead on but everything else was off. I wound up having to turn the speed ring back down to the 3 in 325 to get it to shoot right. Without it even being taken out of the case prior to that does anyone know why I would have had to do that?? I did make a kill that day but I was blown away by the adjustments I had to make when it was shooting fine the week before.

[awshucks]

Humidity, light, diff in rest, scope gremlins?

[JB2010]

Scope gremlins sounds like the problem!