I bought an upper that came with a KAC URX II installed by a KAC dealer. I thought I would like it, but it's a little heavier than I prefer and I'm a fanboy for Keymod. At first I thought I was SOL and put it up for sale, but if somebody has a KAC barrel nut wrench I can borrow, I'm going to remove the rail and keep the BCM upper and barrel.
