>>96728147
well, if it's wild west, the kind of firearm shifts from civil war, practically revolutionary war, to more or less start of WW1 firearms in less than 30 years.

So I'd say leave them exactly as is, the bog standard shit is the smoothbore renaissance stuff except it's trigger action flintlock, but "magic" versions start getting all the new technological upgrades, since magic is basically a form of technology in fantasy settings.

A percussion cap pistol is one with an artificer's "Repeating Shot" infusion as its enchantment.
Rifling is replaced by an enchant that ignores long range penalty, so a pistol increases to 90 no disadv and a musket to 120.

And then for the GOOD good magitech shit, you use the DMG stats for modern weapons. Revolver, Hunting Rifle, Shotgun. Automatic Rifle for Gatling Guns. But of course obviously that needs specialized ammunition, breech loaders and revolver chambers need proper ass machined rounds, with bullets and cartridges, not just lead shot you can make around the fire like that scene in The Patriot where he's melting down his dead son's toys into balls to kill his murderer's with.