How Do I Make My Gun JUST Semi-AutoMatic?

Change the Input.GetButton to Input.GetButtonDown It only checks for when the button gets pressed. Hope that helps :)

This should work for you:

 private var shooting = false;
 var shotSpacer = 0.1; //time between shots in burst
 var burstSpacer = 0.5; //how long after a firing burst you must wait to fire another
 var burstShots = 3; //number of shots in a burst
 private var remainingShots : int;
 var projectile : Rigidbody; //your bullet object
 var speed = 5;
 
 function Update () {
     if(Input.GetButtonDown("Fire1") && !shooting){
         BurstFire ();
     }
 }
 
 function BurstFire () {
     shooting = true;
     remainingShots = burstShots;
     InvokeRepeating("Fire", 0, shotSpacer);
     yield WaitForSeconds(burstSpacer);
     shooting = false;
 }
 
 function Fire () {
     if(remainingShots > 0){
         clone = Instantiate(projectile, transform.position, transform.rotation);
         clone.velocity = transform.TransformDirection( Vector3 (0, 0, speed));
         remainingShots --;
     }else{
         CancelInvoke();
     }
 }

by default it will fire a burst of 3 bullets but you can change the variables to suit your needs.

Scribe

 canShoot : float = false;
 
 coolDown : float = 0;
 
 coolDownMax : float = 2;
     
 function Update(){
     
 if(coolDown < coolDownMax){
        coolDown += Time.deltaTime;
        canShoot = false;
     }
     
 if(coolDown >= coolDownMax){
        canShoot = true;
     }
     
 if ( Input.GetButton ("Fire1")) {
     
     clone = Instantiate(projectile, transform.position, transform.rotation);
     clone.velocity = transform.TransformDirection( Vector3 (0, 0, speed));
     canShoot = false;
     coolDown = 0;
      Destroy (clone.gameObject, 4);
      
     }
     
     }

This is untested code but I think it will work. Tell me if there are any errors. Also, the time between each shot is 2 seconds. You can change this by changing the coolDownMax variable. Tell me if you need anything else :)