Another View

[Johnny Peppers]

I must have missed your mention of the blown primer in your original post. The blown primer is certainly more of an indication of an overload than the hole blown in the top of the cartridge case. Had the picture of the blown primer been shown in the original post, I would have wholeheartedly agreed that there was an overpressure problem.

The chain of events started by the overpressure load could certainly have caused the breechblock to seperate from the receiver face prematurely, allowing a partially unsupported case to rupture through the extractor groove. It was most probably the gas escaping through the blown primer that did the damage the the extractor and breechface as indicated by the smearing of the cartridge case on the breechface.

Under normal conditions there is approximately 1/32 of unsupported cartridge case ahead of the cartridge case extractor groove in the extractor cut, and no unsupported case ahead of the extractor groove in the feed ramp area.