Guffy, I had a raccoon like you once. If I put a rubber fishing lure in a jar with a lid on it he would play with the jar for hours. Take the lid off and he would grab the fish, look at it, throw it down and wander off. I bet I could give you a dial calipers and get the same affect.
I don't know Roy Dunlap and if he wrote anything that made sense I suspect you twisted it around. I don't really care what you think either. Military chamber and brass specs are different than SAAMI specs. Period. The headspace is not even called off the same area of the shoulder. How many load books have warned about excessive pressure using milspec brass in SAAMI chambers because the brass is thicker? I have seen many empty cases that were stuck in the wrong gun (Yes, I was dumb enough to do it too) and it was not an illusion. The short cases soon became very long cases and the shoulder was definitely moving.