Mark Novak's latest Youtube video details work he did on a Schegelmilch prototype carbine from the 1890s. Very interesting, very unusual gun (probably the only one in existence) with an interesting provenance, but the really good aspect of the video is how a skilled gunsmith analyzed the problems, determined how the thing worked, and then made the parts to restore it to a functional condition. A lot of gunsmiths are parts installers. This is gunsmithing taken to another level. There are 'smiths in Canada who can do this sort of thing.