Greetings,

Black Powder is a primer for the Adventure System. It provides a starting point for a setting that uses black powder weapons ranging from 15th century Europe up through the American Civil War. Alternatively, it can be incorporated into a mythical setting if the referee wants to make firearms available in the campaign.

https://www.drivethrurpg.com/product/303836/Adventure-System--Black-Powder

Enjoy!