A total beginner using a setup for loading .30-30 who then knew enough to switch powder......but did not change the auto-charger setting - or so we were told. The person was a US serviceman visiting his dad, a DoD employee. He had never reloaded ANYTHING before that morning.
The four surviving cartridges contained the highly compressed loads, and yes, it was the second shot that blew the poor old gun up.
tac