Abstract: A shooter sighting down the rib of a shotgun aligns the front sight, at the end of the rib, with a target using one eye. An improved blinder is described which prevents alignment of the front sight and target from crossing over to the other eye and a resultant missed target. The blinder is detachably mounted on the barrel of a shotgun and comprises an upright portion which is positioned in engagement with one side of the sighting rib rearwardly of the front sight by a pair of spring clips which underlie the rib and grip the barrel. The blinder is formed of spring metal and the inner surfaces of the clips are coated with polytetrafluoroethylene to prevent scratching the finish of the barrel.