Top is a Model 13-2 mated to a 581 barrel

Gryf, do the center pin and latch match up?
There was a gunzine writer who had an underlugged barrel, apparently a 581's, on a Model 12. Kind of neat looking.

I could be interested in a Model 19-586 combo to get a little more muzzle preponderance on a K frame.

The short PPC guns were in response to a set of rules that provided for 4" and snubby events without enough restriction to hold it to real service and hideout guns. So short bull barrels and heavy ribs were seen for a while. I think that has been changed, but I am a long while away from PPC.