Well I'm off to a rough start....first all the issues with the barrel being shipped back and forth and no sooner does that get squared away and I'm looking at a rail that has a poor fit; This is an MI SS rail for an AR-10, I assumed with the Armalite threads that an Armalite rail would fit right. I haven't torqued the nut yet as it sits in the picture so the rail is going to get further from the notches in the nut while the top rail is already hitting. Am I doing something wrong with the inst