It was obviously important that the tolerances between the collar and the cylinder had to be quite tight so as to protect against chain firing and these guns had respectable tolerances of .002."
The cylinder had a ribbon spring that pushed the chambers against and over the protruding breech end of the barrel that created a near perfect gas seal. There was a square pin that locked the cylinder in position when cocked. The cylinder was pulled back and rotated by hand then the spring would push it back into the locked position as the chamber was aligned with the barrel. The cowling fit tightly over the exposed chambers, again protecting it against chain fire.
The frizzen does indeed have a reservoir for priming powder and a simple toggle and rotating measure that only dispenses the right amount of prime each time and closes both when in the firing position and when it is in the fired position. Seems like Collier did everything right with this gun. Not to say chain fires or frizzen reservoirs never ignited, Might be why there are only a few of these left in existence.
I always assumed this gun was extremely complicated, but the video showed an amazingly simple design and I wonder if the gun were recreated by CNC technology and the tolerances were even better how it would fair? What a cool gun. I think there are only like 10-12 of these in existence today? There is no record how many were made-- estimates are in the 250 range. Collier was an accomplished engineer that worked on many things other that guns, and he seems to have lost interest in the gun business. If he had kept going, who knows how far this would have gone? He also had long-gun versions.
In the first model that he submitted for military trials, the prototypes had a more complex wind up spring system that turned the cylinder automatically when the gun was cocked, but it was discarded in the simpler second model that was made for the commercial market. There is a later third model that was a percussion cap ignition. Very cool Mr. Collier!