Well here’s a theory, first let me ask if there should be a o-ring inside the shroud where threaded end of shroud seats against the barrel nut? What I think might be happening is lead dust is leaking past the flats of the barrel nut dispersing lead dust back onto the barrel sleeve? That would explain the lead on only 1/3 of barrel sleeve? But why is lead getting there in first place? Ya guy’s I’m stumped on this one, I looked at my RW and a little lead dust on barrel “evenly spaced around circumference” plus it’s a different style of shroud/diffuser.