03-02-2014, 03:02 AM
The funny thing about primer signs is that they are a terrible indicator of pressure. I'm reading this old reloading handbook from 1936, where they have a graph of three series of case heads with primer indentations clearly visible after the cartridges were fired.
They were using a radial pressure test gauge, which was common for that era. Anyway, they document how even uncharged cases showed flattened primers.
Some primers on 70,000psi loads look just like the primers on 50,000psi loads, while one of the 70,000psi loads blew the primer entirely out.
![[Image: 2014-03-01193508_zps63e7d8ed.jpg]](http://i1085.photobucket.com/albums/j422/LRRPF52/2014-03-01193508_zps63e7d8ed.jpg)
They were using a radial pressure test gauge, which was common for that era. Anyway, they document how even uncharged cases showed flattened primers.
Some primers on 70,000psi loads look just like the primers on 50,000psi loads, while one of the 70,000psi loads blew the primer entirely out.