I'm posting this up for a friend of mine.
Sidearmor .750 barrel mount Tri-Rail. It is not an MCM mount as the rails on this are fixed. Unit is new, he has never used it because it does not fit his rifle. $80 shipped to anywhere in the lower 48.
I don't have this rail in my possession so all info will have to be obtained through him.
You can contact him at berrylm1974 @ yahoo.com (take the spaces out). Be sure to put something in the subject line about "rail" or "AR15" or "Sidearmor".