JonD,
Sorry, no more barrels on eBay(fleabay) since they thumbed there noses at us sportsman and banned most gun parts and ammo components.
I have not as yet to start my stubbing projects, finishing the shop first. I did get a few barrels from a local gun show. I even bought them without any background checks or anything(poke at the anti firearm community).
The barrels I got were takeoffs from various brands for who knows why. I didn't see any problems down the "tube".
As to how it is done, use the search and read the various posts from Canon6 and others. Seek the wisdom of Quickdtoo also, he is a straight shooter.
Thanks,
Paul