How to learn about different handguns?

[CMcDermott]

There's also some Charter Arms 9mm revolvers out there as well, but I'm not sure if any are 9X19 I think they're in some weird 9mm flavor like 9mm Largo.

Actually they were in 9mm Federal - a rimmed version of the 9x19 that Federal, working with Charter, brought out to see it fail in the popularity contest of the firearms market.

Another good book for you to get is "Cartridges of the World", answers many questions about todays popular cartridges and where they came from. Also has a sampling of old "obselete" cartridges, both black powder and failed smokeless powder examples, as well as some of the european cartridges, military cartridges, and a few of the "wildcat" cartridges.