I don't know if this problem exists for other scopes, but it's something I've just noticed on my Super Sniper. When setting zero, what you need to do is first determine zero, loosen screws holding the windage and elevation knobs in place, set knobs to zero, and finally retighten the screws. The problem is that when you retighten the scews, the sharp ends of the screws are actually putting deep conical indentations to the brass material inside. A problem will now arise when you need to rezero and only slight adjustment is needed. As you attempt to retighten the screws, they'll tend to go back into the grooves that were previously formed. I spent a few range trips and many bullets before I decided to pull off the knobs and see what's going on. It was frustrating resetting the knobs over and over and having nothing change!
Fix: I pulled off the knobs and filled the grooves with JB Weld to give me a new surface to work with. I'll let you know how this works out when I return to the range to check my zero.
Fix: I pulled off the knobs and filled the grooves with JB Weld to give me a new surface to work with. I'll let you know how this works out when I return to the range to check my zero.

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