I'm on the fence because I kind of have this idea of different gangsters fighting a turf war in 1930s definitely not Chicago. The elf gang running around in Zoot suits fighting an orcish gang with the PCs being recruited for membership in definitely not The Untouchables.personally i don't think any sort of automated firing gun would be desirable in DnD,
pistols, revolvers, shotguns, rifles and even perhaps some form of grenades launches, yes, sure, but i don't think anything that creates a stream of continuous hot lead is going to be beneficial for gameplay.
if you can't imagine seeing it in a western or a pirate movie i don't think it should be in DnD.
YepWith 5.5 True Strike, Cantrips are pretty good WITH firearms!
not that "fanning the hammer" was a real thing any professional seriously did.Even in the Old West with six shooters, you had "fanning the hammer" as a technique.
As long as its single action.Even in the Old West with six shooters, you had "fanning the hammer" as a technique.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.