Cat: So, we’re making a setting for a slightly home-brewed Pathfinder 1e campaign. We want guns in the campaign, but the official firearms rules are irksome.
Cat: Anyway, as one of the changes we’ve made, we’ve switched propellants to a technically magical explosive called Force Powder. Force powder is smokeless, does not foul the workings of a gun, operates just fine in water, and can only be set off with a sharp percussive force; examples include smashing it against a metal surface with a hammer, or an explosive shockwave.
Cat; Among other things, we’ve figured that this will probably make rifled firearms a fair bit more popular early on than in real life; one of the big reasons they weren’t widely adopted for military use is because all the smoke quickly nullified their range and accuracy advantages. It also means that matchlocks, wheel locks, and flint locks basically don’t exist, with only percussive ignition being feasible.
Cat: So, are there any other things we should be aware of?
Lucifer: We’re uncertain of the effects on breech-loading firearm adoption. It seems like it should help?
What happens when someone casts Dispel Magic on the Force Powder? When a character in possession of Force Powder-based ammunition is struck by sonic damage, is that enough to set it off? I like the idea of an errant summertime thunderstorm turning the tide of an entire war.
Lucifer: The specific container of Force Powder is ruined, though any other powder on your person is fine. It also won’t ignite in an Antimagic Field.
Lucifer: As for sonic damage… we honestly hadn’t thought about that? But it doesn’t seem like that should cause an explosion.
What about thunderstones?
I’m hung up on the “sharp percussive force” which my brain translated into “a loud bang.” By saying that, you’re removing friction from the reaction. Your powder is extremely less stable than black powder.
Maybe that would mean your firearms are more like RPGs than rifles because the precaution went from “don’t light it on fire” to “insulate it from sound.”
Lucifer: we explained that part badly. What we meant is that you have to physically crush it (and quickly too) to set it off.