So, I finally broke down and ordered a BRN 180s upper. My hope is to build an ACR style rifle that works better than the Bushmaster offering. The system seems to be reliable in what I've read since it's introduction and I honestly hoped to see more on this board. Looking for recommendations on folding stocks; I'm probably going to go with the 180M lower, so that will necessitate a 1913 attachment for whichever stock I do go with. Looking for any other bits of wisdom, advice, etc.. It's on backorder, so no idea when the upper will be in-hand. Lower is not back-orderable yet, so they must be a ways out from having any stock. Anyway, I have plenty of time to figure out this build, so dump it in!