Before trying this procedure, acquaint yourself with the target that accompanies this explanation. It begins with Step 1 and progresses sequentially through Step 5. Note that the Aim Point is the same for all shots on the target.
Draw two 3 inch circles separated vertically by about 2 inches on a 6 x 9 inch piece of cardboard. Place the cardboard target in a safe backstop 10 feet away. Put on safety glasses, you will be hit with lead fragments. The bullseye will look blurry at this close.
Adjust the scope's magnification as low as possible and the parallax adjustment as close as possible. If your first shot is not on the cardboard at 10 feet, tape the cardboard to a larger piece of paper and shoot again . Your pellet holes will show where you're off.
Adjust the scope knobs to bring the shot directly below the Aim Point. The distance the shot is below the aim point should be equal to the distance that the center of the scope is above the center of the bore. That will usually be 2-3 inches.
Move the target to 10 yards/meters and shoot again. You should now be able to adjust the scope's magnification to the maximum, but keep the parallax ring set at the 10 yards/meters or the point where the target seems sharpest. Shoot another two shots to see where you are grouping.
Adjust the scope to bring the shots in line with the Aim Point and striking about 1 1/2 inches low.
Move the target to 25 yards and shoot again. Adjust the parallax ring to make the target appear sharp at this distance. The pellet should strike very close to the Aim Point. I use 25 yards because thats the distance of my yard, but any distance between 20-30 yards is okay for this step.
After shooting a group to determine where the pellet is striking, adjust the scope so the pellet strikes the Aim Point. When it does, the rifle is sighted in. A pellet rifle sighted in this way and shooting 800-900 fps will be on target from 20-30 yards. It will be low when shooting closer than 20 yards and further than 30 yards.