Gun Jesus Ian McCollum examines an inline, rotating breech single shot gun. The cylindrical nature of the breach makes it appear to look like a turret gun and is rather clever. Undated and its maker is unknown, had it been around it would have made a nice infantry carbine for the 1840s.
https://youtu.be/ny63rQ9ecnM
https://youtu.be/ny63rQ9ecnM