From publisher blurb:
Call to Arms is a book line for players and gamemasters alike. Each book focuses on a different type of item, expanding rules for those items and adding everything from new mundane and magical examples of the item to new character options related to the item. Call to Arms: Fireworks and Primitive Firearms focuses on the earliest uses of gunpowder and the many different weapons of war made to use it. Starting with a general discussion of how the powder was made and improved, to how to integrate these facts into your own setting, the book moves on to introducing advanced rules for the creation of explosives and fireworks that either function as single-use firearms or simple, controlled explosions of fire and light. The capstone primitive firearm from the time period this book focuses on is the introduction of various handgonnes which were the first weapons a modern gun-owner would recognize as a true firearm. Finally, in addition to new rules for firearms in general an entire collection of magical explosives and fireworks is detailed, along with new magical wondrous items, cursed explosive powder, a mythic boomstick, an artifact of impressive destructive power and much more.