I just double-checked for the possibility of a "case mouth crimp" by the chamber step-down with a dummy round. The chamber cast I did conforms with SAAMI specs. The dummy round after dropping the carrier on it had an OD of .376 both going in and coming out. A fired case had an OD of .381 at the case mouth. All of this indicates to me dimensions are performing as they should. The step down diameter in front of the case mouth prior to entry to throat proper in the chamber measures .359 (which includes the .002 delta for diameters as per SAAMI spec).
The consistent indicator of an anomaly I see in almost all of my fired brass that show signs of extensive gas leakage is the slight asymmetric compression of the rim. That compression is more pronounced in the failed brass.
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"Everyone speaks gun."--Robert O'Neill
I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!
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