I kinda came down this same path about two years ago and ended up with a 3.75" bbl birdshead Vaquero in .45 Colt.
Not doomsday, just independence. I know how many primers my local firemarshall is willing for to have at the house, and I have that many. Rather than get into casting my own lead, I got a guy accross town who does that for me...
Under Federal law, with a broad brush, any one who can legally own a "firearm" is also legal to make small quantities of BP for personal sporting or personal cultural use. The law isn't worded that way, but it is pretty much the same questions, are you a citizen, are you a felon, are you an alcoholic. I have no idea what the state and muni laws are in your jurisdiction.
Besides .45 Colt, and epecially if you don't want a single action, I would be curious to know how a bullet around 240 grains chronos out of a .44magnum, say 4-6" bbl.
The thing I notice about .45Colt, compared to 9mm and 38Spec and a host of other "modern" cartridges is the case capacity is huge. Enormous. And this with modern smaller capacity not ballon head brass. .41 magnum is probably worth a look, and .327 magnum _might_ worth a look depending on one's tolerance for penetration and flexibility in bullet selection.