There are indeed some very useful images in that thread...
It might be helpful to point out that these chutes should be thought of as a feature of a particular aircraft type and not part of the gun per se. In the same way, the ammunition feed chutes and spent belt collection systems varied from type to type.
On the lMG 08/15 the spent casing is simply ejected forward from a round hole under the barrel. It was up to the individual aircraft designer to decide where and how to route the ejected shell casing from there. Later Fokker types used these types of deflector trays. Albatros fighters routed the casings through pipes to exit below the fuselage. What about Fokker Eindeckers? Pfalz and Roland types? I dunno...
