It is possible I am wrong but I have never noted that on my 2 M82s and 3 Lyman Alaskans?? I haven't used them in the last few years either though. Such movement is obvious on the German, Russian
and British
scopes of the time. If it is moving as you say I must be wrong. I would just get it zeroed at 100 yds and have the point centered but slightly high than center. That will give you more adjustment for long ranges. Maybe Jim Gaynor or Chuck will come by and set me straight. I doubt there is anything wrong with the scope. My memory is apparently another story.