I would not buy one of the pre-production Rugers in .480 with 6-shots...From the reason they gave alone on why they stopped production is enough to scare me. I think I'll just stick with .44 Magnum.
Once upon a time there were huge 6 shot revolvers made by Century MFG.
They made big 6 shot revolvers in 45-70, .444 Marlin and even a 50-70.
There was rumors a while back about the name being bought and production was to start up again, but I have not heard anything lately.
Sure I like to just shoot my handguns, but I got my big bore handguns for hunting. If I want to just plink, I will grab one of my .22 LR handguns.
As for your comment on the 480 Ruger, if you want to shoot light loads, reload.
As for your gateway cartridge, what are you referring to, a lighter round that can be used, such as the 38 in a 357 Mag?
I don't buy big caliber handgun with the intent on using a special or lighter loads in it.
Century sold the rights to Super Six Ltd, who still makes the Bison Bull Super Six to this day:
www.bisonbull.com