help with procedure to summon moving entity based on player direction

I am trying to create a procedure that will shoot a projectile (eg fireball or egg) in the direction the player is facing when the player right-clicks a custom item.

Currently, my procedure shoots a fireball in odd directions that aren't where the player is facing (I was using the look x y and z position with raytrace blocks in a spawn block with vx vy and vz).

Does anyone know how I can make it shoot it in the correct direction?

Thanks

     -Itsmetheking