Originally Posted by John_Deer
It's not hard to see squirrels over 50 yards away. When there are a few leaves on the trees it's much easier to see the squirrels. It really depends on the height of your scope mount. You want to be able to make shots from 10 yards to 100 yards. I would sight the gun in for 60 yards or more. If you sight the gun in closer you will have to much arc in the path of your shots.
Sighting the rifle at 50 yards will not effect ballistics. The "arc" is determined by ballistics. It has nothing to do w/ scope height or zero range of a scope.
If the scope is zero'ed at 100 yards it falls to -3" at 150 yards. At 75 yards it is less then 1/3rd" high. This is w/ a 20gr gamepoint. Here is a ballistics calculator. If you check, on most calibers the zero range improves w/ a higher scope. The standard is 1.5".
You need to know the bullet and velosity. You can play from there.