I have thought about what it would take to build a .50 cal from a barrel for a while, so the way these people did it was of interest to me.
Production of a .50 cal barrel from stock, now that takes some serious work. Could be done, but not a simple homebrew project!
Yup, trying to make a barrel from scratch would be problematic. I see barrels at gun shows quit often foe under $200. They are military discards but still useful.