I'm gonna go against the grain a little here an recommend a model with an adjustable rear sight such as the Ruger Black Hawk. Same classic "cowboy" looks and handling but much more versatility.
Being able to quickly and easily dial POI to POA with any load you ever choose has many advantages. The only disadvantage to the gun would be IF you were to ever compete in an event that didn't allow the adjustable sight. At that point you'll be looking for an excuse for another gun anyhow.
