I was just at the range and this is the 3rd time this has happened to me in the past 3 trips to the range. I check the zero on my scope with two shots and it's dead on at 100. A bit of an issue because I zero my scope for dead on at 200 (2" high at 100). I make the adjustments and it seems fine...about 2" high which is where I want. I go out to 200 and the first shot is fine...right where I would expect it vertically (horizontal was a wind issue today). My next 3 shots end up going low...like 3-4" low. I go back to 100 to check my zero and it's a touch low at 100 (not the 2" high like I set it). The zero seems to have fallen back down on me as opposed to 2" high at 100. I checked all my mounts, rings, action screws etc and everything seems fine. Is this a scope issue? I'm using a Busnell Legend on my 30-06 right now. That'll change soon because I ordered a Leupold due to my fear that my scope is right pooched and I don't want to have equipment failure this fall when "the shot" presents itself. I know I'm not the greatest shot out there but my 100 yard 3 shot groups are usually around 1". These past few range trips left me scratching my head! Could this be a heat issue...the last few times out to the range were fairly warm. I normally take my .22 and shoot it after 1 or 2 rounds with the '06. Perhaps I'm not letting the '06 cool down enough between shots? Either that or my scope isn't holding the adjustments. This has happened to me on the past three range trips. My scope doesn't seem to be holding the zero...either that or I'm not letting it cool down enough. Any help is appreciated.