Thanks for all your comments. It is a Kassnar imported gun and it is not the firing pins hanging up since it does it when the gun is empty. There is also no perceivable difference if the hammers have been dropped or not. So it seems that it is a lack of clearance either at the lug on the barrel or between the forend iron and frame or both. I am quite aware of how easy it is to remove metal and how hard it is to replace since I have been doing some kind of metal work all my adult life from goldsmithing, blacksmithing, machining, knife making and many years in high tech building and repairing assemblies that had tolerance requirements of .0001". I've also built a few .45's that function well and are quite accurate as well am currently in the process of rebarreling a Savage .22 magnum to .17 HMR as well as repairing or rebuilding numerous other firearms. But, I have never worked on a double barrel shotgun with this kind of problem and thought the members here could offer some useful advice. When I applied ink to the bearing surfaces of the forend iron and barrel lug and then tried it, it is obvious that some portions are bearing more than others. I guess I will continue with my careful stoning until it lightens up.
