This is how I made an adjustable plugged case for my 32-40. It falls into the CBE category.  Crude But Effective!  The components are shown below.
Drill and tap the base of the case for 1/4-20 threads.  If you have access to a lathe the next steps are easy.  Then can be done in a drill press with a file if you have patience and some skills.  Loctite the two brass nuts to the screw and turn the diameter to fit the case mount.  Leave the screw slot in place until after the next step.  Cut a slot in the threaded end of the screw with a hack saw.
Reduce the diameter of the brass insert that is designed for use in wood to be a tight fit into the case.   Epoxy it into the bottom of the case holding it with the well greased screw to so the screw is out of the case base.  When the glue is cured, file or grind off the original screw slot and reinsert in the case assembly using a thin screwdriver inserted from the case base.  You may have to experiment with the screw length and possibly mash the threads a ting bit if it will not hold the adjustments, but it will allow you to easily adjust the seating depth at the range.

Jack