SpaceShooter Tutorial instanced asteroid not taking GameController game object in unity5

I've been messing around with this tutorial for some time and I've been stuck on the same spot forever. So I feel that the issue is something I'm just glazing over. Everything was working fine up until I tried to count the score. When I added that line it throws the error: The asteroid is not destroyed and the bolt is not destroyed it passes right through and continues on. As a test I set both the GameObjectController and gameController to public and checked to see what they were set to during run time. At run time the both variables are set to "None*." This adds a new wrinkle. If the gameController is set to null it's supposed to throw an error. It does not.

Below is the code for the GameController and DestroyByContact. I know this tutorial has been questioned to death. I've dug through a lot of threads and comments trying to find the answer to my problem, no luck. I've added comments to try to better understand my code. If something is absolutely wrong could you please let me know so I can better my understanding. Thanks!

Destroy by contact:

 public class destroyBycontact : MonoBehaviour
 {
     public GameObject explosion;
     public GameObject PlayerExplosion;
     public int scoreValue;
     public GameController gmCTRLR;     //create var of class GameController to connect addscore to GameController script 
     
 
 
        void start()
     {
         GameObject gameControllerObject = GameObject.FindGameObjectWithTag("GameController");     //find instance of GameController attach to GCO
         if (gameControllerObject != null)
         {
             gmCTRLR = gameControllerObject.GetComponent<GameController>();
         }
         if (gmCTRLR == null)                                //if not connected
         {
             Debug.Log("cannot find 'GameController'");      //return error to console
         }
     }
 
     void OnTriggerEnter(Collider other)     //on contact preform
     {
         if (other.tag == "Boundary")
         { return; }                                                                             //if contact with boundary, ignore
         Instantiate(explosion, transform.position, transform.rotation);                         //spawn the explosion
         if (other.tag == "Player")                                                              //if contact with player
         {
             Instantiate(PlayerExplosion, other.transform.position, other.transform.rotation);   //spawn the player explosion at player position
         }
         gmCTRLR.AddScore(scoreValue);               //add scoreValue to gamecontroller
         Destroy(other.gameObject);                  //destroy contacting object
         Destroy(gameObject);                        //destroy self
         //gmCTRLR.addScore(scoreValue);               //add scoreValue to gamecontroller
     }
 }

Game Controller:

 public class GameController : MonoBehaviour {
 
     public GameObject hazard;
     public Vector3 spawnValue;
     public int hazardCount;
     public float startWait;
     public float spawnWait;
     public float waveWait;
 
     public GUIText scoreText;
     private int score;
 
     void Start()
     {
         score = 0;                      //on start set score to 0
         updateScore();                  //refresh score display
         StartCoroutine (SpawnWaves());  //run in parallel to game code
     }
     IEnumerator SpawnWaves()
     {
         yield return new WaitForSeconds(startWait);     //give the player time to get ready
         while (true)                                    //spawn waves
         {
             for (int i = 0; i < hazardCount; i++)       //spawn a some number of asteroids
             {
                 Vector3 spawnPosition = new Vector3(Random.Range(-spawnValue.x, spawnValue.x), spawnValue.y, spawnValue.z);     //pick a random spawn location within the bounds
                 Quaternion spawnRotation = Quaternion.identity;                                                                 //pick a random rotation
                 Instantiate(hazard, spawnPosition, spawnRotation);                                                              //spawn the rock
                 yield return new WaitForSeconds(spawnWait);                                                                     //wait a bit to spawn the next rock to prevent accidental collisions of rocks
             }
             yield return new WaitForSeconds(waveWait);      //wait some time to spawn next wave
         }
     }
     public void AddScore(int newScoreValue)
     {
         score += newScoreValue;             //add new score to existing score
         updateScore();                      //refresh score display
     }
 
     void updateScore()
     {
         scoreText.text = "Score: " + score; //change the score display to the new score
     }
 }