Hope this info will be helpful.
This one gives a visual indication of what primer strength is about.
Primer pics. (https://www.6mmbr.com/primerpix.html)
This is a mechanical test
Primer Strength (http://www.castingstuff.com/primer_testing_reference.htm)
Keep in mind there is no test that measures the temperature curve over time for primer ignition, so we get an idea of it from tests like these.
https://www.targetshooter.co.uk/?p=2662
https://www.targetshooter.co.uk/?p=1471