No, it will not reset zero. That adjustment is to correct parralax. So for instance, your target is at 50 yards, if your scope is turned to the 50 yard setting, the crosshairs on your scope should be on the same focal plain as your target. When focused correctly, it should appear that the crosshairs are painted on the object. When you move your eye in relation to the scope eyepiece, the crosshairs should not move, provided the scope does not move. If i were you, I would place a target at 40 yards distance, turn that yardage adjustment to 40 yards, and dial in your crosshairs until you are hitting your target consistantly, USING THE SAME PELLETS. Then when you start shooting targets at different distances, you need to record on a notepad what distance the target is, and where you are actually hitting, in relation to where your crosshairs are. Use known distances when finding out this data.
Then, when you have all that data, you can pick a target (usually within 10-60 yards), focus your scope on it, turning the focus from least yardage to most, and turning slowly, stop when the target and crosshairs are both focused together. Look at what yardage the scope says they are focused at, and adjust your holdover/holdunder accordingly.
Does all that make sense?
If not, maybe someone else can explain it better.
