Prop your arm on a stable rest and aim at the paper target starting with a 25 yard distance. If it prints close to the bulls eye at this range, it will most likely hit the paper at 100 yards. Using the center shot to establish pattern, adjust to bring that shot to center at 100 yards using the same system. Usually the dials move in 1/4" increments up and down which will move you from point of impact to the correct point of impact.
It's best to let the barrel cool between shots to get a more accurate zero.
A scope will be brought back to zero for resighting by the following: Align your scope before you zero. Using a collimator, which is an optical device that attaches to your muzzle and adjust your reticle until it is centered on the collimator.
You can also bore sight from a resting position and once you are on paper at 25 yards you will still have to do a sighting in from 50-100 yards using your scope dials to manipulate your crosshairs and bring them to zero for this particular gun.
Most Leupold scopes have micrometer-style elevation and windage adjustments and a click for each adjustment division can be both felt and heard so scope adjustments can be made without looking at the knobs.
The letters on the elevation and windage dials refer to the direction that the point of impact of the bullet is moved when an adjustment is made so moving the windage to the left will bring the bullet to the left.
Sighting in a gun with a variable power scope is an advantage because starting out you are closer to the target and as you increase the distance you can increase your power so you can see the group on the target.
Adjusting the magnification should not interfere with the adjustments to the reticle or crosshairs.
The Redfield Rangefinder has a lithium battery operated distance calibrator that is useful for measuring distances while hunting or golfing. Accurate up to 800 yards and has a speed gun function that will measure speeds over 300mph.
The Redfield rangefinder displays distances in feet, yards, and meters.