Isn't that the one could fire unlocked, resulting in the breech plug blowing out and rearranging the shooter's complexion?
They couldnt fire unlocked any more than any other break action, but as Overkill said the early breech plugs were unthreaded & held in place like a shotgun shell. There were rumors of blowouts when the gun was opened quickly on a hang fire or the operator got heavy handed capping the nipple and the charged ignited with resulting chaos. I dont know if any were ever substantiated or a case of "what if?". There are still many in use to this day.
