A toy air gun and in particular an improved air gun for generating vortex rings are described. The gun is designed so that the path along the axis of air motion from the rear of the gun to the air exit hole is optically transparent, and contains patterns normal to this axis that assist in accurate sighting. This allows targets to be directly sighted along the axis of air or vortex ring travel. Together with improvements to ensure purely axial air motion, this dramatically increases the aiming accuracy of this class of gun and makes it suitable for target-type activities. A screen with a cylindrically symmetric pattern of openings and aiming marks prevents solid objects placed inside the gun's barrel from being projected outwards, and assists in aiming the gun. An vented safety guard at the exit end of the gun prevents large pressures from developing in the event that the gun exit is blocked while preserving the vortex ring component to the airflow.