Greater Magic Weapon

Level: Acolyte 4, Mage 3; Components: V, S, M/DF; Casting Time: Attack action; Range: Close (25 ft. + 5 ft./2 levels); Target: One weapon or 50 projectiles (all of which must be in contact with each other at the time of casting); Duration: 1 hour/level; Saving Throw: Will negates (harmless, object); Spell Resistance: Yes (harmless, object)
This spell gives a weapon an enhancement bonus to attack and damage of +1. This bonus increases to +2 at 8th caster level. An enhancement bonus does not stack with a mastercraft weapon's bonus to attack.
Alternatively, the caster can affect up to fifty arrows, bolts, or individual bullets, or a single magazine of up to 50 rounds. The projectiles must be of the same type, and they have to be together. Projectiles (but not thrown weapons) lose their transmutation after use.
A caster can't cast this spell on a natural weapon such as an unarmed strike