An eight-shooter from over 400 years ago. But those who wrote the constitution could never have imagined a multi-shot firearm.
Am I seeing a barrel-mounted, spring operated indexing pawl which engages tiny notches in the front of cylinder between the priming pan covers? On the other hand, maybe that lever on the right side behind the cylinder is part of the index locking mechanism.
Now what we need is a gas-operated, automatic firing, flintlock chain gun artillery piece.