Make On Target effects when using a Cast on Strike weapon Cast on Swing
So most cast on strike weapons have an on-touch effect. However a very select few such as Trueflame have a Target instead of On Touch. Despite this, they function almost identically to their On Touch variants, which makes the difference indifferent.
What would be neat is that when you swing your weapon that has "On Target" spell, it would shoot out the projectile even when it hits thin air. Thus such an enchanted weapon could be used for both close and ranged combat. Here´s the thread I made about this subject: