I called S&W, and told them what was happening and they gave me a fedex shipping label. I appreciate all of the replies.

I was worried about the bolt being out of spec too.

barrel is 5.56, and the entire BCG was disassembled and lubed with CLP after the first outing. Problem continued second time out.

I have never had the gun feed, and that has me concerned. I think shipping it back to them is the most efficient route, since they can spec everything and make sure it's operational.