A bore sighting assembly for accurately mounting a telescopic sight on a rifle or other firearm, with the sighting assembly utilizing a laser beam generator for creating a beam having a diameter of less than that of the bore, and with the light being directed axially through the bore onto a remote target. In addition to the laser generator, the bore sighting assembly includes a guide for controllably directing the beam from the generator through and along the axis of the bore for impingement onto a remote target. The guide includes eccentric bushings for adjustably positioning the laser generator in the receiver area of the rifle or firearm, and a beam control disc may be secured to the distal tip of the barrel for additional guidance and control of the laser beam.