Correctly mounting and sighting a red dot sight or scope can improve your accuracy when shooting a rifle. There are many types of red dot sights, from the simple tube scope to the electronic laser sights. You can purchase a red dot sight from a number of suppliers and installation is relatively universal.
Disarm the weapon. Remove the clip if your firearm has one. Open the breach and remove any ammunition. Double-check your work to ensure there are no rounds in firearm. Leave the chamber open. Put on safety goggles.
Remove the two screws securing the rear sight to the gun using a Phillips screwdriver. Slide the old sight off of the mounting rail and remove it from the rifle or shotgun.
Loosen the locking nuts of the two rings that secure the red dot sight and slide the rings into the grooves on the sight. Look through the sight and adjust the rings so the elevation adjustment is facing upward and the cross bolts are facing the same direction. Tighten the locking nuts.
Loosen the mounting screws on the red dot sight rings and slide the cross bolts onto the mounting rail of the gun. Make sure the cross bolts line up with the appropriate slots on the rail. Hold the gun in firing position with your right hand and adjust the red dot sight so that it is approximately three inches from your eye when aiming.
Tighten the mounting screws on the red dot sight until they are firm. Do not over-tighten or you will damage the mounting rail.
Hold the gun up towards the light and inspect your work. Ensure that the sight seats properly on the mounting rail by looking for any light filtering between the two surfaces. Remove and re-seat the sight if the cross bolts do not line up with the mounting rail.