Amongst the Skulls and Shackles - A Pathfinder Campaign
Emerging Guns: Firearms become more common. They are mass-produced by small guilds, lone gunsmiths, dwarven clans, or maybe even a nation or two—the secret is slipping out, and the occasional rare adventurer uses guns. The baseline gunslinger rules and the prices for ammunition given in this chapter are for this type of campaign. Early firearms are available, but are relatively rare. Adventurers who want to use guns must take the Craft
Firearms feat just to make them feasible weapons. Advanced firearms may exist, but only as rare and wondrous items—the stuff of high-level treasure troves.