A rifle sight - accessory or lens?

Hi xkaes

There is a wide variety of hardware which allows a scope to be attached to a rifle but you won't find a tripod bush being part of the equation.

Typically, you will have two mounts which will fix the scope to the barrel, the mounts being either side of the adjustment screws which handle vertical and lateral axes. Modern scopes such as the one you have pictured offer a greater variety of adjustments but the principles are the same for this old Yashica scope. Focusing here is done by twisting the eyepiece and fine alignments and corrections are made using the screws near the centre of the sights. The time-consuming element in adding sights to a rifle is in achieving perfect alignment with the barrel; it can take a few shots before you succeed. Once perfect alignment is achieved, you can then make corrections for distance, elevation or wind as required using the adjustment screws.