So its like the direct feed bbmg design in which you get air coming from the back of the hopup while the bb's feed up into the hopup and are introduced into the air stream.. there is one difference though, the bbs are fed with the assistance of pressure as well.
Pretty much what im saying is.. if you didnt have air feeding the bbs up into the hopup chamber and you used a spring feeding the bbs up, it would be exactly the same was my direct feed bbmg design posted earlier.
It is very cool though since it uses the same kinda principle as the coiled up looking gun as well..
EDIT: The guy also has a picture of a T-shaped Vortex gun out of PVC.. Seems like he must know of this site or at least neospud, or burntelake.
So hopefully if anyone knows him on here you should convince him to post on here and talk about it