So...sounds like what I'm experiencing is fairly common with the 375 HH (or any other belted magnum). One way to deal with it is to create a false shoulder so the cartridge headspaces on this false shoulder. If I prep my cases using this method will the stretch not occur? Where does the brass come from that blows the shoulder out - the neck? The second way to deal with it is to treat it like any other cartridge and just set the should back .002 or so after the first firing and live with the initial stretch as the case forms to the specific chamber. If I follow this course of action will that initial stretch greatly shorten case life?
With a cartridge design (belt) that has been around for a hundred years or so one would think there would be a standard setup procedure for dealing with this idosyncracy.
