Whether you're target shooting or hunting, using a riflescope can greatly increase your accuracy. To benefit from your scope, you must sight it in -- align the intersection of the scope reticle with the spot where the bullet will strike the target. The instruments for adjusting the reticle are the windage and elevation adjustment dials centrally located on the scope body. Scope click values are generally considered the distance on a target that the projected point-of-impact will move with one click of the adjustment dials.
Determine the minute of angle (MOA) of your scope dials. This value is commonly marked on the face of the dial; if it is not, consult the manual or contact the manufacturer. Most scopes have an adjustment of 1/4 or 1/8 MOA. Fortunately, MOA measurements conveniently equate to approximately the same measurement in inches at a distance of 100 yards. This information is the basis for calculating scope clicks.
Determine the range of your target in yards, preferably in increments of 100 yards.
Using a scope with a 1/4 MOA at a range of 100 yards as a base line, you would increase the value of each click as your range increases and decrease the value as it decreases. For example at 100 yards, a 1/4 MOA scope will move the point of aim 1/4-inch with a single click. If the range is increased to 200 yards, the value of each click doubles to 1/2-inch; at 300 yards to 3/4-inch and so on. Conversely, if you decrease the distance to 50 yards, your click value would decrease by half to 1/8-inch.