A longgunner asks please:
Handguns...what is a good small concealable DA/SA revolver, .38 to .44 cal, 3" +/- bbl with xposed hammer? Don't understand the alphabetical sizing...j k l m

Derringer = belly gun no matter the cal. (nope)

What revolver fits the size of an open hand kinda like the Walther PP series?

Next up pocket or pocket holster? (I know, I know, hammer or nub for S/A)

What are the alphabet sizes, small to large, with the below considerations/reccommdation for each.
Cals?
IWB or OWB comfort?
Concealability?