I feel sorry for the person involved and wish him a speedy recovery.
I had my own incident with priming going bad twice now. The first time was with my RCBS Turret Press priming with the priming assembly as supplied but WITHOUT the safety tube installed. I was changing from large primers to small primers and the tube wouldn't seat properly, so I removed it but couldn't see anything. I then took an EMPTY tube and tried to seat that and POW a huge bang and a face full of soot.
There were two small rifle primers in there that were jammed up and they both detonated. Would have been very bad if I had of used the full tube.
Second incident was with a RCBS hand priming tool that used shell holders.
I was priming 264WM brass using Fed 215 primers and one case felt funny as I squeezed, so looking at it, the shell holder was off a little, so pushed it home and proceeded to get the entire thing jammed up, couldn't remove the case or shell holder from the tool and the primer was not sliding back out into the tray.
So I removed the tray, which had about 40 primers in it still, and started manipulating the shell holder and handle at the same time to try to free up what was happening and next thing I know is a deafening bang and ringing ears.
I was not hit by shrapnel or anything, but there was a partially seated primer in the case, and 2 others under it. I do not remember putting ANY force on the handle at all, yet the primers detonated.
Both times I was lucky, I never load tubes now unless I have a safety shield of STEEL between me and the primers.
I understand that some primers have a new compound that is even more touchy than Lead Styphanate….be careful people.
Cheers.