At least some of the "Custom Shop" barrels were made by MGM, although T-C may have finished and marked them. I have several that are T-C marked but also have MGM-identified parts (a VR on a 28 guage Contender barrel for example, and another on a .410). Not sure what the relationship between the original T-C and MGM was, but I sure would be interested to know. I now get all my "T-C" barrels from MGM.
Mesa..when the custom shop closed, a TC dealer bought out all unfinished and partially finished blanks & barrels, & remaining inventory.
They were then contoured, cut, crowned, chambered, and finished by MGM.
those barrels are identified by the dual stampings T-C / MGM.
i ended up with 7 of them, all are fine shooters.