Re: Severely Dented Cases….Secondary Explosion Effect?
I see it as a puzzle, and would love to learn the actual cause.
The cases seem not merely failing to fully expand at a local area. They're seem formed INWARD there.
And, there is no discoloration within the form. The sooting stops at the necks/shoulders.
I can think of nothing that would cause external to case pressure greater than internal case pressure.
If it were a pocket of powder late igniting there would be discoloration from it.
Any interference with full expansion would just cause that, and not inward formations.
The inward formation is what throws me.
Is it really inward, or was the brass sized so much under chamber that it's really a local failure to expand?
I don't see any SINGLE possibility as a cause, but some rare combination of factors.