Zeroing in your rifle scope with a laser is an expedient method with a fair degree of accuracy. However, laser beams provide a straight line between the rifle barrel and the target; lasers cannot compensate for bullet trajectory. Trajectory is the amount that the bullet descends as it loses inertia; the further the distance, the greater the bullet drop. To zero your scope for bullet trajectory, you need to use live ammunition.
Zeroing with Live Ammunition
Set up a paper target, at the desired distance, on a rifle range. Load your rifle with three bullets, take careful aim at the center of target and take three controlled shots. Check your target and mark the center of your shot group. Adjust your scope crosshairs accordingly. On most scopes one click of the adjustment dial will move the crosshairs approximately 1/4 inch (based on a distance of 100 yards). So, if the center of your shot group is one inch below and one inch to the right of the target center; you will need to move your cross hairs one inch up and one inch to the left. Turn the vertical adjustment (the dial on top of the scope) four clicks counter-clockwise and turn the horizontal adjustment (on the right side of the scope) four click to the left. Load your rifle with three more bullets and take three more controlled shots. The shot group should now be centered on your target. If further adjustments are needed, repeat the procedure until your bullets are consistently hitting the center of the target.