Try leaving the first 3 links empty and hook the first link on the little tab that projects to the right on the feed tray. Make sure that the feed cam is all the way to tlhe left and you should be able to close the top cover and latch it. Pull your cocking handle back and release it and it should advance and chamber a round. You might have to cock it twice to get it to feed, some work the first time and some seem to have to be cocked twice, like an M2HB.
I don't think that will work because I am using desintegrating links. I'll keep messing with it, but it is not much of a PITA. I am just glad it is running.
How did you finally configure the gas tube?
I did the unthinkable.... I actually followed the plans and ordered the materials that SS recomended.