
Castarr4 |

I think I disagree with your premise.
Weapons Light and one-handed bludgeoning weapons, spears, and arrowheads can all be made of stone. Weapons made of stone have half the hardness of their base weapons, and have the fragile condition.
I see nothing indicating that a firearm can be made out of stone, and so they can't be.
I could see an argument for stone ammunition, and can't see anything in particular in the rules against it... but the list seems to be of the "these are the only things that can be made of stone" variety, rather than "weapons such as ___ can be made of stone." So I'd rule against it in my reading of the rules.
Further, if it worked, your ammunition would have the fragile quality. There's no rules for what happens with fragile ammunition, but in my game, that would probably mean that a misfire would be especially bad, as the bullet shatters inside your gun and is going to take significantly longer to clear out than a normal misfire... RAW, there's no difference though.
Take this a step further. If you made your gun out of stone in my game, the fragile quality would cause it to break when you roll a 1. Rolling a 1 also causes a misfire, which makes a broken firearm explode. Your gun wouldn't last very long.
YMMV

cnetarian |
"Light and one-handed bludgeoning weapons, spears, and arrowheads can all be made of stone."
Firearms do Bludgeoning AND Piercing damage. This would seem to disallow stone firearms since they deal both types of damage.
As a simple practical matter stone is not an acceptable medium for firearms. Firearms work at high pressures and are only as strong as their weakest point and rock has lots of weak points (early firearms blow up because early metallurgy produces weak points).
Dwarven stone crafters may be able to make firearms out of stone, probably similar to modern ceramics techniques, and get rid of the flaws/fracture line in stone. I'd house-rule stone firearms made by dwarves at +20% cost and +50% weight AND let them be two-handed firearms (with no loss in damage) using stoneplate as a model if someone wanted them.

Gauss |

Actually stone ammunition is historically accurate. It was much easier to make than metal ammunition. However, I do not know if broken stone ammunition would have ever caused damage to the firearm. To be honest, I doubt it. First, at the time of stone ammunition only smoothbores would have been used. Second, if the stone broke it would just act like a shotgun.
On the other hand rifled barrels would require the close tolerance of a metal ball or bullet and would be unable to use stone ammunition without some loss of power.
- Gauss
Edit: BTW, I would never trust a stone gun. It would shatter way too easily. I would definitely start it with fragile and maybe even the broken condition.

Castarr4 |

If you can...They're still destroyed on a 1, unless you find a way to eliminate your misfire chance.
If a fragile weapon is already broken, the roll of a natural 1 destroys it instead.
Early Firearms: If an early firearm with the broken condition misfires again, it explodes. When a nonmagical firearm explodes, the weapon is destroyed. Magical firearms are wrecked, which means they can’t fire until they are fully restored (which requires either the make whole spell or the Gunsmithing feat).
It doesn't matter which effect you apply first, fragile or misfire. It's still destroyed or wrecked.
So, while arguably possible, I'd still consider it a bad idea.

Castarr4 |

My current conclusion:
Firearms: Can be made with stone according to RAW. It's a bad idea because they'll explode immediately on a 1.
Ammunition: Can not be made with stone according to RAW. Logically it would make sense to be able to make ammunition from stone. Seems to be a cheap way to make 1/4 price ammunition. You're already getting 1/10 cost ammunition from Gunsmithing, after all.

Castarr4 |

I have trouble believing that this is for flavor purposes, seeing as stone cuts the cost of the weapon to 1/4. So... you want to have 1/4 cost firearms without the explicit drawback of being fragile? For flavor purposes? I like most of your posts, BBT, but I think I disagree on this one.

Michael Radagast |

Eh, I like the flavor, especially for a dwarf. No crazier than half the special materials out there acting like other materieals...ironwood anyone? If you'd like to tax it, maybe require an alchemical salve, to keep it from breaking? Otherwise, I don't know...call it ore-stone or hardstone, give it matal stats, bump the price maybe and be done with it.
I like maintaining reality as often as possibly, to ground the fantasy...but this doesn't have to be one of those cases, I think.

Castarr4 |

Well, if you're keeping the fragile quality, I think it would be reasonable to make a gun out of some specially treated stone. Inadvisable, perhaps...
And also on kinda shaky ground rules-wise, in my opinion. I think ranged weapons are meant to be treated as a separate category from light/1H/2H weapons. Firearms have their own tables though, which confuses everything. I think firearms made of stone, obsidian, and bone are probably against RAI, even if it can be argued that they're legal by RAW.

mdt |

Rule of thumb :
If it fits the world, and the character, and he get's no continuous benefit from it, hand wave it and go for it.
For example, if you have a dwarf gunslinger, and he wants his guns to have been a ceramic MW heirloom his grandpappy baked for him when he was born, then go for it. Same weight, same stats, small increase in cost for rarity.
Yes, he may get some benefits down the road (like it not reacting to a magnetic spell or field), or having some extra resistance to fire or something (with a corresponding vulnerability to sonics). But basically, it's just a hand gun made of ceramic instead of ironwood or steel or mithral or whatever.
Now, what if he wanted a handgun made of 'extremely light but high tensile ceramics' that would be easier to wield? Sure, slap the cost and modifiers for Mithral on it, and call it 'Ghost Ceramic' or something. Want it to have a 20 hardness? Slap the price mod for Adamantine on it and call it 'Resolute Ceramic'. Same thing for weapons and armor. If a druid wants a set of full plate made from ceramics... fine with me, same as if you did iron wood or dark wood. Just pay the extra cost you would for ironwood/darkwood armor and call it ceramic.

Gnoll Coward |

If you actually want it to be structurally unsound for flavor reasons, I don't see any issue with offsetting the cost with fragility.
Personally, I can't see dwarves building anything that wasn't designed to last. As a result, I'd probably go the opposite direction - assume it was constructed using the same alchemically-strengthened stone crafting techniques dwarves used for stoneplate, and increase the cost, weight and durability accordingly.

Gauss |

BlackBloodTroll, Orthos is referencing the episode where Kirk fought a Gorn. Made a gun using what appears to be a bamboo tube, quartz for ammunition and concocted gunpowder on the fly. Mythbusters later showed that the gunpowder was not viable and if it was it would've done just as much damage (if not more) to Kirk than to the Gorn.
- Gauss