List of weapons with reduced specials
From Ephinea PSO Wiki
It is a common misconception that weapons with a 9-star rarity or lower are reduced (i.e. their specials have lower activation rates and steal/drain less HP/TP/EXP from their targets) and those with 10-star rarities or higher are unreduced with some exceptions. The actual rule is every weapon with a hex value less than that of Photon Claw will be reduced if it comes with a special that can be reduced (i.e. not sacrificial or elemental damage) and it attacks more than one time or is capable of acquiring more than one target per attack (excluding cards). Specials of all other weapons are unreduced.
Swords (reduced by 1/2)
Daggers (reduced by 1/2)
Partisans (reduced by 1/2)
Slicers (reduced by 2/3)
Mechguns (reduced by 2/3)
Shots (reduced by 2/3)