Yesterday I acquired a Kreighoff, Semper Model, 44 cm long, insert barrel assembly. It is chambered for the .22 Winchester magnum cartridge and is for a 16 gauge chamber. My question is, does anyone know how, or know a source of info, to make the necessary adjustments to fit it to the chamber. The square-drive screw, which draws back the tapered “shoe” and locks the assembly in place, is pretty straightforward. However, I’m not so sure about the purpose of, and the proper adjustment of, the two smaller sliding “shoes”, which are each held in place by a pair of tiny fillister-head screws.