Hold a little mirror up tight against the objective lense, and look through the scope. You should see two sets of crosshairs. When a scope is adjusted back to zero, you will see only one set, as they are right on top of each other. Look through the scope and adjust the windage and elevation controls and see if the reticle moves or not. If it doesn't move, then the scope is junk.
Or, if you have a grid type boresighter, you can adjust it and see if it moves. I just don't like to stick anything in the muzzle of my rifles, so I don't use them.
Good point..
