I have a crusty old Security Six that is 1,352 rounds into it so far. No problems noted. Nothing significant to report.
On the other hand, just for giggles, I once tried to see how long a New Vaquero chambered in 45 Colt would last firing only black powder cartridges. At slightly over 50 rounds, it was completely bound up to where I had to turn the cylinder by hand for each shot. But it sure smelled good.