Library / Magic

Unerring Weapon

Grants a +2 bonus, +1 per four caster levels, on attack rolls to confirm a critical hit.

This spell causes a weapon to veer closer to vital areas, improving the result of a critical threat. This transmutation grants a +2 bonus on attack rolls to confirm critical hits plus 1 additional bonus point per four caster levels (maximum total bonus +7). If the spell is cast on projectiles, the effect ends on a specific projectile whenever that projectile is used to make an attack, regardless of whether the attack hits. For this spell, shuriken are considered projectiles.

Source: Ultimate Combat
one weapon or 20 projectiles, all of which must be together at the time of casting
Casting
System
PF1E
School
Transmutation
Subschool
Element
Casting Time
1 standard action
Range
close (25 ft. + 5 ft./2 levels)
Target
Area
Duration
1 round/level
Saving Throw
Will negates (harmless, object)
Spell Resistance
No
Components
V, S
Class Levels
Components
V
S