DougK
Actually, there were different versions of 9.3x72R available, 9.3x72R D (Deutsch), 9.3x72R E(English), 9.3x72R N( NORM.- standardized)( this was designed to fit most of the others and allow easily reaming the chambers of the rest to fit), and 9.3x72R S&S (Sauer and Son)( an entirely different cartridge based on a larger diameter case). From your description, it seems you may have a "D" version rifle, which is the "2-taper chamber" mentioned. Modern ammunition is the "N" version. Of course, absent a chamber cast, there is no way to know what you have. In my experience, if a cartridge is fired in a "D" chamber( by resizing or forcing it in), then it is fireformed to the chamber and can be loaded with "N" dies, which would function as neck sizing dies. If your load expands the head diameter enough to make chambering difficult, it is likely too hot. I suspect it is something else causing the interference. You can "smoke" a case or color it with a magic marker and push it in with some force. When you extract it, it should show the location of the interference. You might be surprised how many 9.3x72R reamers exist.
Mike
