This is mine, but it is my shot measure, not powder, although at one time I used it with powder.
I never had it discharge, obviously. Of course the loads I was using with it, was .030" wet patch with water based or Mink Oil
and .682" ball in a .690" bore.
With these, there is ZERO chance that there is a burning ember left in the bore - ZERO. Thumb started combinations are just
looking for just such an accident though, as-in leaving a smoldering ember of cloth, in the bore, to ignite powder poured in. Of
course SWABBBBBING should extinguish that quite well. I did see one go off just as the fellow thumb-started the next patched
ball. Burned his hand quite badly.