PRD
Greater Magic Weapon
Gives a weapon an enhancement bonus on attack and damage rolls of +1 per four caster levels
Transmutation \ Elemental School metal 3 \
antipaladin 3, bloodrager 3, cleric/oracle 4, inquisitor 3, magus 3, paladin 3, shaman 4, sorcerer/wizard 3-level
Save: Will negates
SR: Yes
Casting time: 1 standard action
Range: 7.5m + 1.5m / 2 levels
Duration: 1h/level
Targets: 1 weapon or 50 projectiles
Domain: war 1
Componenent: V, S, M/DF (powdered lime and carbon)
Description
This spell functions like magic weapon, except that it gives a weapon an enhancement bonus on attack and damage rolls of +1 per four caster levels (maximum +5). This bonus does not allow a weapon to bypass damage reduction aside from magic.
Alternatively, you can affect as many as 50 arrows, bolts, or bullets. The projectiles must be of the same kind, and they have to be together (in the same quiver or other container). Projectiles, but not thrown weapons, lose their transmutation after they are used. Treat shuriken as projectiles, rather than as thrown weapons, for the purpose of this spell.
Text from "Magic Weapon" :
Magic weapon gives a weapon a +1 enhancement bonus on attack and damage rolls. An enhancement bonus does not stack with a masterwork weapon’s +1 bonus on attack rolls.
You can’t cast this spell on a natural weapon, such as an unarmed strike (instead, see magic fang). A monk’s unarmed strike is considered a weapon, and thus it can be enhanced by this spell.