[Unclenick]

The anvils can't fit through the flash hole, AFAIK, except maybe with some of the NT cases with enlarged ones. So they are coming out with the primer and flying off somewhere. The fact they are no longer attached to the primer cup is of no consequence. All that matters is that they were there when the primer was struck by the firing pin to provide something to crush the priming mix against. If they somehow did make it through the flash hole, the brass they are made of would not harm a bore.