I'm surprised by the fact itself that there are actually rifles with a hammer under the chamber (which has some interesting ergonomic differences). But even more interesting is the fact that there's such a rifle with a magazine system beeing really, really close to what I did with one of my never released LEGO gun prototypes. What I did was to place multiple cartridges in a row and add a rubber-powered, flexible hook thingy inside the magazine slot to force it int position. This way I would just need to push the magazine to get a new chamber ready for fire. And here's how the one great unsual rifle does it - it simply uses a a cylinder to lock the chamber. Hm, maybe I should just try it again one day.
However, it's cool to such a construction beeing alive somwhere.