An embodiment of a fitting assembly includes a fitting having at least a solid outer body, a pass-through bore, and at least one undercut region. The pass-through bore is defined by at least one pass-through bore wall, extending longitudinally through a length of the outer body from a first end to a second end. The at least one undercut region is formed into the at least one pass-through bore wall, and includes at least one expansion bearing surface disposed radially outward of at least one contraction bearing surface.