I had a partial case head separation using a 1.8oz buffer

[BluntForceTrauma]

Been listening and learning and mulling this over and a technical question arises regarding brass materials science: What is the minimum pressure in PSI required to deform cartridge brass, to obturate it to the chamber walls? Can't find this answer by Googling, or my Google-Fu is weak.

This is relevant to what pressure might possibly be required to be residual in a case to cause the case web area to balloon into a "belted magnum" as it is in the process of being extracted from the chamber during an early unlocking event.

Apologies if this was asked and answered earlier.