If you have been following my threads you will see I am trying to get together parts to build a 9mm on an Ar15 lower. Have a barrel coming but I need an old no longer good gas block to use for installing a standard type handguard that I already have. Needs something for that front ring to rest against. So if you have one that is no longer any good I sure could use it. or have a thought as to what I might use in place of one for a .650 dia. barrel please let me know.