Consult the Damage by Caliber table above for help figuring out what damage roll to use for your specific weapon. Add in the number of number of Characteristics Score worth of range. Where the weapon has a set range, just divide it by 18 and round up. Subtract the amount of ammo from 17 and subtract that number from the cost so far. If the gun has more than 17 ammo, just add 1 to the cost for each additional round.
Revolvers are always non-automatic.
This includes more than just basic maintenance. If part of a gun needs to be replaced or repaired, use this skill. This also allows the character to invent new guns, either by using pre-existing parts or machining brand new ones. There is no need to choose a specialization. However, this skill does not include heavy weapons such as those listed under Gunnery.