Nikon enjoys a well-deserved reputation for producing quality optics, but the company is known mostly for its cameras. However, it also makes quality rifle scopes. A good scope is important for accurate, long-range shooting, and Nikon makes good scopes. Proper use is just as important as the scope itself, though.
Install a boresighter into the muzzle of your rifle and line it up with the Nikon scope as closely as you can.
Look through the scope. You should see two different sets of reticles, or crosshairs. One is the scope itself; the other is the boresighter.
Adjust the elevation and windage on the scope so the crosshairs overlap and only one set is visible.
Remove the boresighter.
Test the scope by firing a round at the target.