Looks like you'd have to use a predetermined powder charge to ensure the forward touchholes would line up with powder. I wonder if the touchholes forward of the charge being fired could be securely held shut to keep venting to a minimum. And, if a shot failed to go off, I guess you could try shooting it out with the next charge in line instead of pulling it.
This looks like a predecessor to the Lindsay musket of the 1860s. That one was loaded powder-ball-powder-ball, but instead of a movable lock assembly, the hammer was split so the two halves hit on separate nipples. The first trigger pull dropped the hammer onto the forward nipple, the second pull dropped the hammer on the rear one. Not too surprisingly, both charges going off at once was a problem - the rear minie ball was the 'gas seal' to keep fire from the forward charge going off from setting off the rear charge. If these flinters used patched RB, that might have given more protection from multiple discharges.
An interesting find. SCL
