Paul, that is a good idea, thanks for sharing it.The moral is...never throw anything away !
I have had a few primers go off too, but mainly due to poor primer pocket swaging(berdan for ex-MIL)or poor placement on the anvil by myself. Inside the very protective die you can hardly hear it, but gets a bit warm and is very dirty to clean up!
Some de-luxe Lee Loader kits include a little priming tool with fixed shell-holder. Could be worthwhile though a bit tedious and not as good as the magazine load Lee Auto-Prime of course.