muzzle flash and particle emit didn't show when shot

Here is my code, I attached this to the launcher position.And drag the mesh and particle to the slot. But anything happened when shot. Also ,I don't understand " enabled = false" usage in function lateupdate(), may be confused with "muzzleFlash.enabled = false;" but when I deleted "enabled= false",I can see the muzzle flash. But particle still not been seen. Anyone can give help?

 var projectile :  Rigidbody;
 var speed = 150;
 var fireRate = 0.05;
 var damage = 5.0;
 var reloadTime = 5;
 var range = 1000;
 var bulletsPerClip = 30;
 var clips = 20;
 var muzzleFlash : Renderer;
 var nextFireTime = 0.0; 
 var m_LastFrameShot = -1;
 var hitParticles : ParticleEmitter;
 var force = 1;
 private var bulletsLeft;


 function Start()
 {

     bulletsLeft = bulletsPerClip;
     hitParticles = GetComponentInChildren(ParticleEmitter);
     if(hitParticles)
     {

         hitParticles.emit = false;
     }

 }




 function Update ()
 {


     if( Input.GetButton("Fire1")&&Time.time > nextFireTime)
     {
         nextFireTime = Time.time + fireRate;
         FireOneShot();
     }
 }



 function FireOneShot()
 {
     var ray = Camera.main.ScreenPointToRay (Vector3(Screen.width/2,Screen.height/2));

     var hit : RaycastHit;
     var hit2: RaycastHit;
     var ourTarget : Collider;
     var direction;

     if(Physics.Raycast(ray,hit,range))
     {
         Debug.DrawLine( transform.position, hit.point, Color.red);

         Debug.Log(hit.point );   


         direction = (hit.point - transform.position).normalized;

         if (Physics.Raycast(transform.position,direction,hit2,range))
         {
             if (hit2.collider.tag == "Enemy")
                 hit2.collider.SendMessage("ApplyDamage",damage);


             if(hitParticles)
             {

                 print("hitparticle");
                 hitParticles.transform.position = hit.point;
                 hitParticles.transform.rotation =
                     Quaternion.FromToRotation( Vector3.up, hit.normal);
                 hitParticles.Emit();

             }

         }
     }


     bulletsLeft--;
     m_LastFrameShot = Time.frameCount;
     enabled = true;
     print(bulletsLeft);

     if(bulletsLeft ==0)

         Reload();



 }


 function LateUpdate()
 {
     if(muzzleFlash)

     {

         if (m_LastFrameShot == Time.frameCount)
         {
             muzzleFlash.transform.localRotation = Quaternion.AngleAxis(Random.Range(0, 359), Vector3.forward);
             muzzleFlash.enabled = true;

         }


         else {
             muzzleFlash.enabled = false; 
             enabled = false; 
         }
     }
 }




 function Reload()
 {
     yield WaitForSeconds(reloadTime);
     if( clips > 0)
     {
         clips--;
         bulletsLeft = bulletsPerClip;
     }
     else
         print("You haven't enough ammo");
 }

 function GetBulletsLeft ()
 {
     return bulletsLeft;
 }

 function OnGUI()
 {
     GUI.Label(new Rect(Screen.width-128-100,228,200,128), "BulletLeft:" + bulletsLeft);


 }