Swing-out action, single barrel shotgun

Saw this auction for an odd .410" shotgun barrel on ebay.  It didn't have a hinge point like usual single-shot, break-open weapons, so I was tempted to buy it because of how unusual it is, but I don't really have the time for another project.

The barrel is from a Firearms International model Garcia Bronco, .410".  Sometimes these skeletonized weapons were known as "bicycle guns," because they could be folded up and stored underneath a bicycle's frame.  The barrel rotates like a modern swing-out revolver.  The barrel appears to be held in place to the rotating sleeve assembly by two pins, but there must be more to it than that?  Perhaps it's pressed in or threaded in?  One flaw I could possibly see in this rotating action is that everything seems to be hanging on a relatively thin solid rod which is also used as the axis of rotation - what would happen if that bent?

It's not really as rare as I had thought because people are finding this thing in pawn shops for less than $100.  The simplicity of the action makes this seem like it would be easy to replicate with simple tools.  Gun Parts Corp is also selling parts for the combo gun.  Chiefly, the barrel sleeve and breach block are relevant to my interests.