Shadows and Sky
The firearms of this world are nothing like the ones of Earth, and use a mix of official Pathfinder rules.
Instead of a physical bullet being propelled by an explosive charge, the guns are loaded with a charged slug of Magicite. When fired, the charge goes off, shooting a magical blast out the barrel, and leaving the magicite slug inert. Magicite slugs can be re-energized by a mage for a price, as long as the slugs are kept.
Magicite slugs are unstable and delicate. Should two slugs touch, their magical energy will discharge. For this reason, ammunition is carefully stored, and repeating firearms are rare. Repeating firearms are typically “revolver style”, with cylinders of cold iron holding the slugs.
Firearm Proficiency: The Exotic Weapon Proficiency (firearms) feat allows you to use all firearms without penalty. A nonproficient character takes the standard –4 penalty on attack rolls with firearms, and a nonproficient character who loads a firearm increases all misfire values by 4 for the shots he loads.
All firearms are part of the same weapon group for the purposes of the fighter’s weapon training class feature.
Attacking: When firing a firearm, the attack resolves against the target’s touch AC when the target is within the first range increment of the weapon, but this type of attack is not considered a touch attack for the purposes of feats and abilities such as Deadly Aim. At higher range increments, the attack resolves normally, including taking the normal cumulative –2 penalty for each full range increment. Unlike other projectile weapons, firearms have a maximum range of five range increments.
Some firearms are marked as “Scatter”, the equivalent of a modern shotgun. Instead of taking a -2 to hit per range increment, it’s -2 damage per increment.
Loading a Firearm: You need at least one hand free to load one-handed and two-handed firearms. In the case of two-handed firearms, you hold the weapon in one hand and load it with the other—you only need to hold it in two hands to aim and shoot the firearm. Loading siege firearms requires both hands, and one hand usually manipulates a large ramrod (which can be wielded as a club in combat). The Rapid Reload feat reduces the time required to load one-handed and two-handed firearms, but this feat does not reduce the time it takes to load siege firearms.
Most firearms are breech loaded. It is a move action to reload a breech weapon, and a full round to refill an internal magazine. Loading any firearm provokes attacks of opportunity.
Misfires: If the natural result of your attack roll is a 1, that shot misses. When a firearm misfires, it gains the broken condition. While it has the broken condition, it suffers the normal disadvantages that broken weapons do, and its misfire value increases by 4 unless the wielder has gun training in the particular type of firearm (see Gunslinger). In that case, the misfire value increases by 2 instead of 4. If a broken gun misfires again, it is wrecked, and can not fire again until repaired.
Damage: Guns shoot a visible magical blast, typically red, that deals force damage. Gunshots are treated the same as Magic Missiles for spells that specifically mention it, like Shield.