Subjective pressure signs, such as primer flattening, head expansion, etc. really aren't very reliable.
For modern center-fire rifle loads in rifles such as the .30-'06 a method which gives safe results is to start with new virgin brass, and to take one case, with your loading tools to the range, and take that one case and reload it ten times to shoot your group, and see if you can detect any loosening of the primer pocket. If the primer still seats firmly after ten reloads, the load is safe.
If the primer pocket gradually loosens enough within ten reloads that you can easily push an unfired primer by hand, by pushing a case held in your fingers against a table top, without using a priming tool at all, then the load is too hot.
If the primer pocket is loose within 5 reloads it shouldn't take a rocket scientist to figure out something is wrong.
This method is not reliable for cartridges developing less than about 50,000 cup.
For modern center-fire rifle loads in rifles such as the .30-'06 a method which gives safe results is to start with new virgin brass, and to take one case, with your loading tools to the range, and take that one case and reload it ten times to shoot your group, and see if you can detect any loosening of the primer pocket. If the primer still seats firmly after ten reloads, the load is safe.
If the primer pocket gradually loosens enough within ten reloads that you can easily push an unfired primer by hand, by pushing a case held in your fingers against a table top, without using a priming tool at all, then the load is too hot.
If the primer pocket is loose within 5 reloads it shouldn't take a rocket scientist to figure out something is wrong.
This method is not reliable for cartridges developing less than about 50,000 cup.
