Making a general statement like;
"...most if not all ammunition manufacturers have tried and failed to replicate it in the lab."
Well, just because it happens to be on hand, the Lee reloading manual states :
then goes on:These conditions must all be present:
1) Very slow burning powders
2) Charge must be 25-35% under normal
3) Something special must happen about which no-one knows the details for certain
Conjecture includes...
Laborotories have been unsuccessful in replicating the event
... mention of the phenomenon is to encourage you to avoid reduced charges of very slow powders
Sorry, he doesn't annotate it so I can't point right now to his Laboratory tests.
Perhaps you know more than Mr Lee? Or have first hand experience to contribute to the common understanding?
I'll also just re-post this:
As always, your safety is in your own hands and everyone has to determine what they're comfortable doing.