It has been my experience that some revolvers will lead the barrel even with proper fitting bullets, and some won't. This can be fixed, but might cost more than some are willing to spend.
The cylinder throat should be about the same diameter as groove, or maybe .001 bigger for best results, but if the timing is off a bit, or the forcing cone is rough, it still might lead.
I have had barrels that were shiny smooth that leaded up bad, and rough ones that didn't, so there are no guarantees.
I had a Ruger Blackhawk in .45 that would not shoot well, and was a real lead mine.
The barrel groove diameter was .456, and the cylinder throat measured .459
I tried different size bullets right out to .460, but nothing worked.
A call to Ruger accomplished nothing, they insisted everything was up to their standards, and I should not be using reloads. Kind of soured me on Rugers for awhile.