Trying to destroy a projectile and "teleport" to another area of the screen when it hits a target.

Hey again guys! I've been pretty active here and I am learning alot by asking you guys for help! I'm still working on another problem with @Quillict, but that's another story. Anyway, my question is this:How do I go about destroying a projectile after it hits a target? This is the set up, so you can understand my code better. I am shooting a cannonball out of a cannon automatically as the scene loads. I got that part of the script right. Now, on the right of the screen I have a Target/bullseye, tagged "Target" that moves up and down at a fixed speed. What is supposed to happen is that once the ball hits the target, it gets destroyed (I'm not going to use preset animation) and gets teleported to the upper right of the screen and falls down, like if the are being collected. Here is my code thus far. Mind you that the fire function was the original code with InvokeRepeating on the outside (moved it inside). Everything else, Update() and OnEnterCollision (), are new.

 #pragma strict
 
 //Attach to empty object, in front of cannon barrel  
 var projectile : Rigidbody; //The cannonball
  
 var fireRate = 2;//Time Delay Between cannonballs
  
  
 function Update()
 
 {
     fire();
     OnCollisionEnter();
 
 }
 
 //dictates the sound effect,and spawns the cannonball at a random velocity
 function fire()
  
 {
  
     audio.Play();
     
     var gunShot : AudioClip;
     
     var instantiatedProjectile : Rigidbody = Instantiate(projectile, transform.position, transform.rotation );
      
          instantiatedProjectile.velocity = transform.TransformDirection(Vector3(0,0,Random.Range(1,5)));
      
     audio.PlayOneShot(gunShot);
     
     
 InvokeRepeating("fire",2,fireRate); //instructions to repeat cannonballs firing
 
 }    
 @script RequireComponent(AudioSource)
 
 //this checks if the object you hit is the object tagged "Target"
 function OnCollisionEnter(collision : Collision)
 
 {
     if(collision.gameObject.tag == "Target")
     {
         //destroys cannonball
         Destroy(collision.rigidbody);
     }
 }

Thoughts? Thanks in advance for the help!