DMing Firearms in a modified Pathfinder campaign

[Calemyr]

Last week I started a new campaign, and one of the mechanics I set up for it I'm still not entirely sure of: the inclusion of firearms in the campaign.

Part of the premise of the story the campaign is built on is that all magic has been sealed up for a bit over a millenia, causing a dark age as the old traditions and religions crumbled in their sudden absence. Then the world got on with life and found out that there were more ways to skin a cat than simply casting Melf's Clumsy Razor, and the world gradually became more "earth-like", including the recent adoption of steam-powered trains for transportation. The players will eventually be involved in a multifactional struggle over a potential rebirth of magic.

I realized early on that removing magic from much of the game would cause troubles with game balance. Magic was, for instance, a critical counter to heavy armor. Heavy armor limits dexterity, reducing reflex saves and touch AC in the process and thus making the wearer particularly susceptible to various magical attacks. So, when I decided on the setting, I tried to use firearms to recover at least some of that balance.

Here are the basic rules I devised:
* Firearms are based on the rulesets of various crossbows for damage, reload time, and such. Pistols are represented by light crossbows, for instance, while rifles use heavy crossbow rules. Multi-chambered firearms use repeating crossbow rules.
* Firearms are touch attacks, penetrating armor more effectively than other weapons.
* Firearms and their ammunition cost 100x more than their respective crossbows. This does not carry over to enchantments (+X is regarded a function of quality rather than magic).
* Firearms are common military weapons in this setting, so they are treated as martial weapons unless their crossbow counterpart is exotic.

The hope is that this will accomplish a few things:
* Counter heavy armor again, as Full Plate is once again no longer the ultimate and only valid protection.
* Drive home that this isn't a usual might & magic style setting.
* Force the players to display a little bit of caution with villagers. A firearm may not do much damage (1d4-1d10 with no real damage mods beyond +X enchantments), but a militia of low level guards could still chew up a fair portion of an adventuring party if necessary.

I write this post because I'm a bit of a greenhorn as a DM, this being only the second campaign I've ever run and the first one was mostly an experiment to test out 4e (which really didn't take). I know encounter size is something I'll need to be careful with, but since the gaming group is currently very small that was a given to begin with.

I'd appreciate any advice you veterans could offer on how to modify or use this mechanic to its best effect in pursuit of an interesting and satisfying campaign.

[Ashtagon]

If a gun is 100x crossbow price, it will NOT be a common military weapon. That's 3500 gp for a pistol or 5000 gp for a rifle, before any special stuff. And at 10 gp per shot, you aren't going to be firing one in a hurry either.

You are aware that crossbows are by default simple weapons, right? Making guns as martial weapons wont really make them more common.

[Calemyr]

If a gun is 100x crossbow price, it will NOT be a common military weapon. That's 3500 gp for a pistol or 5000 gp for a rifle, before any special stuff. And at 10 gp per shot, you aren't going to be firing one in a hurry either.

You are aware that crossbows are by default simple weapons, right? Making guns as martial weapons wont really make them more common.

Crap, you're right, I mistyped that. It should be 10x, not 100x. Enough so that most individuals have to really nurse their ammo, but not enough to be unmanageable.

Most rules I've seen for firearms make them exotic and either ridiculously powerful or so difficult to use effectively that they simply aren't worth it. I chose martial because then anyone with any official combat training could be expected to know how to use at least the basic ones. I also wanted to make them available to bards and rogues, but none of the players picked from those classes, so it hasn't come up.

[Knaight]

I wouldn't make them touch attacks without some other considerations. Even ignoring the fact that early bullets had trouble against plate, that simply makes them too good. Now, there are balancing methods, and cost isn't a particularly good one. Other examples:
1) They take a full round to reload, and can only be fired once a round.
2) They are inherently less accurate than bows or crossbows. -4 to all attacks if allowing touch attacks, -2 to all attacks if they just ignore half of the armor.
3) They make it really, really obvious where you are if you try sniping. Massive clouds of smoke, etc.
4) There is no rapid reload.
5) Get the powder wet, and kiss damage goodbye.
6) If you are hit by a flame, the powder you are carrying goes up with you.

[Calemyr]

See, that's the problem with firearms and why I tried to approach them differently. Removing Rapid Reload is reasonable, and the circumstantial difficulties of messing with gunpowder shouldn't come as a surprise to anyone if such a circumstance occurs (as long as I'm not too malicious with it), but adding a laundry list of complications that hamstring the weapon ultimately makes it functionally unusable.

The catch is that we're mainly dealing with 19th century tech. Jesse James era-stuff (the first session was centered around a train robbery, in fact), just enough for revolvers to be recognizable but not enough to be a common sight. That means more armor-piercing quality and accuracy than muskets and cased ammunition rather than shot and powder.

The expense part wasn't meant to directly effect a player with a gun (they usually have enough liquid assets to keep it loaded), but it does mean that they aren't as likely to buy more ammo than they can carry and that it is harder to come by, since most enemies won't be able to afford much in the way of ammo.

Finally, I'm not particularly worried about firearms tipping the balance in favor of the players (with their small party size, they need every advantage they can get), I'm more worried about the opposite. Like I said, larger groups could chew them up with gunfire.

[Golden-Esque]

See, that's the problem with firearms and why I tried to approach them differently. Removing Rapid Reload is reasonable, and the circumstantial difficulties of messing with gunpowder shouldn't come as a surprise to anyone if such a circumstance occurs (as long as I'm not too malicious with it), but adding a laundry list of complications that hamstring the weapon ultimately makes it functionally unusable.

The catch is that we're mainly dealing with 19th century tech. Jesse James era-stuff (the first session was centered around a train robbery, in fact), just enough for revolvers to be recognizable but not enough to be a common sight. That means more armor-piercing quality and accuracy than muskets and cased ammunition rather than shot and powder.

The expense part wasn't meant to directly effect a player with a gun (they usually have enough liquid assets to keep it loaded), but it does mean that they aren't as likely to buy more ammo than they can carry and that it is harder to come by, since most enemies won't be able to afford much in the way of ammo.

Finally, I'm not particularly worried about firearms tipping the balance in favor of the players (with their small party size, they need every advantage they can get), I'm more worried about the opposite. Like I said, larger groups could chew them up with gunfire.

I allow matchlocks in my campaign. If you're not a gun expert, they're essentially guns that drop small matches into their combustion chambers to fire the projectiles when the trigger is pulled. I prefer these to more modern guns because it keeps the Renaissance-level technology that I'm going for, but also I can justify how I personally balance firearms in my campaign.

My rules for guns aren't really complicated; they're balanced around a pistol (being a simple weapon) dealing 1d4 points of damage at Medium-sized. Your average 1st level creature has 2 to 3 HP, so a good pistol shot can kill you, but its not guaranteed to. Also, while all gun attacks are considered touch attacks (shooting someone in full plate can still dent the armor, which is often more dangerous then actually taking the shot itself), you can't add your Dexterity modifier to attacks made with them unless you have a specific feat, so they're also less accurate if you're not trained with guns.

As of right now, I allow the pistol as a simple weapon, the rifle as a martial weapon, and then oodles of fun guns as exotic weapons. They go from weapons such as the revolver (which mechanically works like a repeating crossbow, but with touch attacks) to special racial guns, such as the vulsunian flameshot (you can shoot the gun as a free action so long as you have a produce flame effect active on you, and the bullets deal additional fire damage). All in all, the biggest thing is to make sure that your firearms make sense in your campaign, and that they're not SO good that they make other types of weaponry obsolete.