OK, it doesn’t fire live ammunition, but it is “working,” in the sense that it’s an accurate 1:1 mechanical replica of the original: it can be cocked, rendered safe, loaded, cycled, field-stripped, and even fired, so long as the load is no stronger than a bit of homemade primer. And though I think the coil springs, at least, pretty much have to be metal parts, the rest of it is nothing more than carefully cut, laminated, glued, shaped, and painted paper.
Dubious? I was. But after watching a bunch of videos from YouTuber Tacome1942’s channel, I am persuaded that this is the work of a very talented, very dedicated, very patient, and pleasantly modest young man who is entirely on the level. Here’s his first video showing off the gun’s action, here’s a full teardown, and here’s one of many tutorial videos showing off his construction method. [Thanks, Righteous Fondue!]