Well, you can mimic a projectile by making a ray from a spot and repeating it
But you would be using lot of psi or it would be limited to 32 range
Unless you want to figure out how to move charges very precisely with the projectile so it can activate it at will. (within 5min of the charge summon or since the projectile runs out)
It would be probably be limited to 20 executions or to one projectile at time and being within distance to execute the spell (32m)