Serious benchrest shooters are the world's most picky scope users when it comes to mechanical durability/ repeatibility. The rich ones use March scopes or have something like a Leupold with the internals frozen and use adjustable mounts. Next down the line is Nightforce followed by Sightron(some are modified with lock screws in the turrets). Many budget shooters use stock Weavers which usually do very well unless you get a bad one.

Several of the serious experimenters have taken to modifying scopes to increase mechanical precision and repeatibility. It seems that all the scope brands ( except March) have occasional problems caused by some combination of poor design, sloppy assembly, loose tolerances. Mostly the problems don't affect the typical hunter or plinker, but do show up in the quest for that last tiny fracton of an inch. in group size at 200, 600 or 1000 yds.

RWO