Lots of info out there iffen ye know where to look, books mostly and some known barrel makers that do video tapes...
2 books off the cuff to get ya started.
"The Gunsmiths Manual" by Stelle and Harrison 1st print 1883 reprinted 1972. For folks willing to DIY the hard way. Gunsmithing by Dunlap 1st print 1950 reprinted 1996 by NRA. Best for more up to date technologies and tools.
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