I started several years ago with a duty issue 4 inch revolver. If you can shoot well with that, you'll love a 6 inch "race gun". I built my fist one out of a S&W 586 frame (because my issue revolver was a 686, I already had several speedloaders). I bought a douglas slab-side barrel and aristocrat 3 position sight from Brownell's catalog. Houge grips, followed by Bill Davis Grips, an extended cylinder release, and I was ready to go. All leather, ammo trays, and shooting box came from Safariland.
After shooting in the California Police Summer games, I met many of the CPPA members, and after shooting in many of their matches over the course of the next few years, I became a life member.
I hope this info helps. If I can answer any specific questions, let me know. Good luck!