Mounting device for fitting a telescopic sight to a fire arm

A mounting apparatus is disclosed for attaching a sighting device onto a weapon. The mounting apparatus has a rail disposed on part of the weapon in a longitudinal direction. The rail has a pair of longitudinally extending opposed sides and a longitudinally extending first attachment element on each of the opposed sides. A removable mounting base has a pair of longitudinally extending side edges and a longitudinally extending second attachment element on each side edge. Each second attachment element is complimentary to a corresponding one of the first attachment elements. The mounting base is slidingly and longitudinally engaged with the rail via the complimentary first and second attachment elements. The mounting base is formed of at least two parts which are slidable against one another in a transverse direction. A spring mechanism produces a spring force and is arranged to bias the two parts of the mounting base into engagement with the rail. The spring force is overcome by manually squeezing the two parts to release the mounting base from the rail.