A telescopic sight mounting system, comprising - a casing, which is fixable to a Picatinny rail by a channel on the underside of the casing being fastenable to the Picatinny rail and on one side of which a recess is introduced crosswise to the channel, - a casing ledge, which is disposed on one side of the channel on the underside of the casing, - a flank, which is movable forward and backward in the recess, the recess being disposed crosswise to the channel on the underside of the casing, in the direction of the casing ledge, - a locking screw, which has an end equipped with a thread and another head-shaped end and which extends first through the flank and then through the casing, the end equipped with a thread protruding from the casing, - a locking lever having a bore of the locking lever for being connected to the head-shaped end of the locking screw by means of a pin and having a surface of the locking lever and having a lateral face of the locking lever, the lateral face and the surface being disposed in such a manner that the lateral face is abuttable against the flank for unlocking the locking lever and the surface is abuttable against the flank for locking the locking lever, and the distance of the bore of the locking lever to the surface of the locking lever is larger than the distance to the lateral face of the locking lever, - an adjusting nut which is fixable to the end of the locking screw protruding from the casing and being equipped with a thread, characterised in that the pin extends longitudinally to the channel through the bore of the locking lever and through a bore of the locking screw at the head-shaped end, and in that at least one recess is available on the outer circumference of the adjusting nut, a ball being able to at least partially engage in the recess, the ball being disposed in the casing between the outer circumference of the adjusting nut and an adjusting screw, and a force being able to be applied to the ball for securing the ball by means of the adjusting screw. - a casing, which is fixable to a Picatinny rail by a channel on the underside of the casing being fastenable to the Picatinny rail and on one side of which a recess is introduced crosswise to the channel, - a casing ledge, which is disposed on one side of the channel on the underside of the casing, - a flank, which is movable forward and backward in the recess, the recess being disposed crosswise to the channel on the underside of the casing, in the direction of the casing ledge, - a locking screw, which has an end equipped with a thread and another head-shaped end and which extends first through the flank and then through the casing, the end equipped with a thread protruding from the casing, - a locking lever having a bore of the locking lever for being connected to the head-shaped end of the locking screw by means of a pin and having a surface of the locking lever and having a lateral face of the locking lever, the lateral face and the surface being disposed in such a manner that the lateral face is abuttable against the flank for unlocking the locking lever and the surface is abuttable against the flank for locking the locking lever, and the distance of the bore of the locking lever to the surface of the locking lever is larger than the distance to the lateral face of the locking lever, - an adjusting nut which is fixable to the end of the locking screw protruding from the casing and being equipped with a thread,