A method for depositing a coating on an interior surface of a hollowed workpiece. The method comprises providing the hollowed workpiece in a vacuum chamber, the hollowed workpiece comprising an interior surface substantially defining a bore having a longitudinal axis; positioning a magnetron within thed bore along substantially the length of said longitudinal axis and substantially radially equidistant from the interior surface, said magnetron comprising an external sputter target material; and, generating a circumferential magnetic field about the sputter target material for a time and under sputter deposition conditions effective to produce an interior surface comprising a substantially uniform coating comprising said sputter target material.