Objective lens adjustment

[Survivor]

I've got a Bushnell Banner 6-25x40.  I can dial the obj lens down to like 20 yr out to 400.  Does that adjustment alter my field of focus or does it compensate for the trajectory by moving the crosshairs up or down?  Maybe that's all wishful thinking. At the range should the scope be at 50 if I'm shooting from the 50 yrd bench and the same for 100?  THNX

[KN]

Your objective lense adjustment is for focusing at different distances only. If its set at 20 you will not be in focus at 400. It does not change the point of inpact or adjust for trajectory. It's main function is to elliminate paralax at specific distances. If your target is 50yds away you should have the lens set at 50, (more or less). Turn the ring until it in focus and don't wory too much about what the markings say. Some scopes, especially the lower priced ones, don't seem to be very accurate in this respect. Just adjust it until its focused.   KN

[quickdtoo]

Parallax adjustment should be done to eliminate parallax, the relative movement of the reticule to the target. Place the rifle in bags or a rest so it's stable and doesn't move, set the AO to the range of the target, look thru the scope without touching the rifle, move your eye position behind the scope a little, the reticule shouldn't move on the target if the setting is parallax free. If the reticule appears to move in relation to the target, adjust the AO until it doesn't move. If that setting is different than the indexing on the AO, make you own markings.

Tim

http://www.snipercountry.com/Articles/Parallax.asp