Shooting with Limited Ammo

I have my shooting script, and to limit ammo:

 #pragma strict
 
 var projectile : GameObject;
 var fireRate : float = 0.1;
 private var nextFire : float = 0.0;
 var hasMuzzleFlash : boolean = true;
 var muzzleFlash : GameObject;
 var bulletsLeft : int = 5;
 private var hasFired : boolean = false;
 private var bulletsPerShot : float = 1;
 
 
 function Update () {
     
     if(hasFired) {
         bulletsLeft -= bulletsPerShot;
 }
 
     
     if(Input.GetKey("space") && bulletsLeft <= 0) return;
     
     if(Input.GetButton("Fire1") && Time.time > nextFire && bulletsLeft > 0) {
         nextFire = Time.time + fireRate;
         var clone = Instantiate (projectile, transform.position, transform.rotation);
         hasFired = true;
     }

     
     if(Input.GetKey("space")) return;
     
     if(Input.GetButton("Fire1") && Time.time > nextFire) {
         nextFire = Time.time + fireRate;
         Instantiate (muzzleFlash, transform.position, transform.rotation); 
 }
 
 }

To make sure that the shooting stopped if ammo ran out, I made it return in that situation:

 if(Input.GetKey("space") && bulletsLeft <= 0) return;

Inside the firing script I made a boolean to make sure it actually fired:

 if(Input.GetButton("Fire1") && Time.time > nextFire && bulletsLeft > 0) {
             nextFire = Time.time + fireRate;
             var clone = Instantiate (projectile, transform.position, transform.rotation);
             hasFired = true;

And I allowed it to calculate the bullets:

 if(hasFired) {
             bulletsLeft -= bulletsPerShot;
     }

Well the only problem is, when I fire once, it never stops subtracting. It begins subtracting and subtracting and it never stops. SO i put it in a FixedUpdate() function (I wasn't sure how that would help, but it's worth a try), and that didn't change. So I put it in it's own function called function BulletCounter()but then it didn't work at all.