In the 1980s and early 90s I made a good living buying and selling double guns, mostly Parkers and L C Smiths. A lot of guns went through my hands that had problems, Hunter One triggers were part of it. I discovered that almost all of the trouble with this trigger is related to stock problems, mainly a change in the spacing on the lower tang. Usually shimming the lower tang would correct it. Many original stocks with single triggers have a steel bushing at the rear tang screw so it must have been a trouble spot. A hunter one trigger must have clearance between the trigger mechanism and the sears for it to shift for the second shot. Rarely did I find problems with the trigger mechanism unless some one had tried to fix it. Jim