I use a Ruger Redhawk 4" barrel with a 320gr WLNGC CastPerformance bullet in front of 21.1gr H110 for my back up carry when hunting. Here is my Revolver and Load and target from my final testing. I am standing free hand at 25yds and the target is a 6 shot group measuring 1". Yes! I think my load is ready.
The little holes are some body's rifle holes, I ran out of targets and used theirs.