The .22LR cartridge is very light bullet, so it comes as some surprise to many novice shooters that .22 rifles have a decent range. Furthermore, hunters using .22 rifles are often pursuing small game, such as rodents. Combine a middling range with a small target, and the need for a properly set scope becomes clear.
Items you will need
Pre-set targets
Boresighter
.22 cartridges
Start by setting up between two to four targets. The typical practical range of a .22 rifle is 100 yards, so set up at least two: one at 50 or 60 yards, and the other at 100 yards. Extra targets can be set up outside the 100 yard range, but don't go beyond 200 yards.
Check to make sure your gun is unloaded. This is a very necessary safety precaution, so don't skip it.
Install the boresighter by sliding it into the barrel.
Take hold of your gun in the proper fashion: primary hand (the right hand for most people) on the grip, secondary hand forward of the trigger assembly on the stock, and the butt squarely set into the shoulder.
Reticle
Look into the scope with the eye that is closest to the eyepiece, closing the other eye. You will see that there are two sets of reticles (crosshairs). One is for the scope, the other is the boresighter's.
Adjust the vertical (bullet drop) and horizontal (windage) controls so the two reticles are aligned.
Double-check the crosshairs by looking at all the targets with the scope. Use greater magnification for targets that are further away. The alignment of the reticles should not change. You have now set your scope.
Remove the boresighter. Fire a few test shots if your targets were set up on a safe shooting range, but otherwise save the shooting for later.