That's a really cool little pistol, Grogan. Especially since you know the history of it, and it's a part of your family heritage. Hard to beat that!
One thing about cap and ball firearms was that you could pretty much ALWAYS get ammunition for one, as caps, powder and lead were commonly available where ever you happened to go in the West, where as cartridges may or may not be available. Sir Samuel Baker, who hunted in the West and who explored the source of the Nile in the 1880's noted that it was much easier to pack for extensive travels with his muzzle loaders, as all he needed was the supply of powder, lead and caps, while with cartridge guns he needed a selection of cartridges for each one, for various circumstances. This was one of the reasons that the Navy Colt was still being sold in the London office until the supply was exhausted in 1880: people traveling to Africa or China preferred something that they KNEW they would be able to shoot, though was perhaps a little behind the times, than have something up to date that you couldn't shoot in the middle of nowhere, exactly where you would need it most.
In Firearms of the American West, Vol. II, there is a quote from a lawman who carried an SAA in .41 Long Colt. He complained that while on a manhunt he couldn't find ammunition for his gun for the life of him, though .44 WCF was available at just about every place he stopped. As a result, though he really like the .41, he replaced it with an SAA in .44-40 as soon as he was able to, just for the availability of ammunition. It was definitely something to think about when traveling the wide open expanses of the West.
My own G-Grandfather, homesteading in the Cimarron Strip of Oklahoma, had a caplock shotgun and a cartridge revolver. The muzzle-loading shotgun was more versatile than a cartridge one would be, and cheaper to shoot as well. The cartridge revolver was for business though, and as it wasn't shot much could use more expensive ammunition.
Cap and ball was used for a LONG time after the introduction of cartridges by folks who either didn't need the latest thing, or were in places where the supply system wasn't the best. Or they just didn't want to spend the money on such foolishness when they needed to use their funds on more important things like seed crops.
Thanks again for showing that little Police. Nice!
Cheers!
Gordon