As magic items go, magic weapons are a staple of all campaigns. Magic weapons have enhancement bonuses ranging from +1 to +5. They apply these bonuses to both attack and damage rolls when used in combat. All magic weapons are also masterwork weapons, but their masterwork bonus to attack does not stack with their enhancement bonus to attack.
Weapons come in two basic categories: melee and ranged. Some of the weapons listed as melee weapons (for example, daggers) can also be used as ranged weapons. In this case, their enhancement bonus applies to either type of attack.
In addition to an enhancement bonus, weapons may have special abilities, such as the ability to flame or the ability to attack on their own. Special abilities count as additional bonuses for determining the market value of the item, but do not modify attack or damage bonuses (except where specifically noted). A single weapon cannot have a modified bonus (enhancement bonus plus special ability bonus equivalents), higher than +10. A weapon with a special ability must have at least a +1 enhancement bonus. Some weapon abilities carry a fixed surcharge rather than being priced as an increase in the effective item bonus.
Caster Level for Weapons: The caster level of a weapon with a special ability is given in the item description. For an item with only an enhancement bonus and no other abilities, the caster level is three times the enhancement bonus, if an item has both an enhancement bonus and a special ability, the higher of the two caster level requirements must be met.
Bonus Damage Dice: Some magic weapons deal bonus dice of damage. Unlike other modifiers to damage, bonus dice of damage are not multiplied when the weapon scores a critical hit.
Ranged Weapons and Ammunition: Masterwork ranged weapon bonuses to attack and masterwork ammunition (arrows, crossbow bolts, and sling bullets) attack bonuses stack with each other (but not with enhancement bonuses).
Unlike most enhancement bonuses, but similar to the way in which armor and shields work together, the enhancement bonuses of magic ranged weapons and magic ammunition stack for attack and damage purposes. So a +1 longbow firing a +1 arrow contributes a +2 attack bonus to the ranged attack roll and a +2 bonus to any damage dealt by the attack. However, for purposes of damage reduction, the enhancement bonuses of a magic ranged weapon and magic ammunition do not stack. Only the ammunitions enhancement bonus is applied against the damage reduction, since it is the only part of the weapon actually striking the creature. So, a +1 longbow firing a +1 arrow contributes a +2 attack bonus to hit a creature with damage resistance 5/+2, but since the arrow itself only has a +1 enhancement bonus, the damage reduction is still effective: 5 points of any damage dealt are subtracted from the damage the creature actually sustains.
Magic Ammunition and Breakage: When a magic arrow, crossbow bolt, or sling bullet misses its target, there is a 50% chance it breaks or otherwise is rendered useless. A magic arrow, bolt, or bullet that hits is destroyed.
Light Generation: Fully 30% of magic weapons shed light equivalent to a torch (20-foot radius). These glowing weapons are quite obviously magical. Such a weapon can't be concealed when drawn, nor can its light be shut off. Some of the specific weapons detailed below always or never glow, as defined in their descriptions.
Hardness and Hit Points: An attacker cannot damage a magic weapon with an enhancement bonus unless his own weapon has at least as high an enhancement bonus as the weapon or shield struck. Each +1 of enhancement bonus also adds 1 to the weapon's or shield's hardness and hit points.
Activation: Usually a character benefits from a magic weapon in exactly the way a character benefits from a mundane weapon - by attacking with it. If a weapon has a special ability that the user needs to activate (such as the sunbeam power of a sun blade), then the user usually needs to utter the command word (a standard action).
Most magic weapons only have enhancement bonuses. They can also have special abilities. A weapon with a special ability must have at least a +1 enhancement bonus.
Specific Magic Weapons