Yes, moly can build up. Kevin Thomas proved that years ago with extensive tests at the Sierra lab.
He found out it built up in the throat area over about a 50-round cycle to the point where accuracy suffered, then the excess blew out and accuracy came back--sometimes.
I often saw the same thing when I was fooling with moly a decade or so ago, which is why I also much prefer DBC .
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
