The primers are not fired, they have what looks like a drop of solder inside them so in the pic, the dark brass is the top/cap of the primer, inside is shiny like solder. They're also larger than a current 12ga primer, comparing a trap load shell to one of these old primers. The tool fits a 12ga shell.
I talked to Dad's cousin, he can not remember any of them reloading when he was a kid, early 1940s.
Thanks for the replies.