RAP4 Detailed Look at DMAGS
Interested parties should check out 4:27, where a U-shaped First Strike feed is used (Edit - the mag actually shown in the video uses smaller shells however). The feed is essentially a broken mobius strip, pretty damn cool really.
By the way, take a moment and look at how far RAP4s production quality of videos has come in the last couple years. This is what every major paintball product showcase should look like in terms of quality.