A problem with GUN FIRE SOUND

I'm having a problem with an FPS game that I'm currently developing. When firing the gun, the sound of it is not very good and sort of "raw". When firing single shots it sounds just fine but when firing on full auto it gets distorted and doesn't sound like a gun supposed to. Also, it seems like while firing on full auto it skips some shot sounds.

Here's A sample that I've recorded of what I mean: http://picosong.com/NxUd/

This is the script I use:

 var ReloadSound : AudioSource; //reload audio source
 var DrySound : AudioSource; //empty magazine audio source
 var FireModeSound : AudioSource; //fire mode switching audio source
 var Shell : GameObject; // bullet shelll 3d object
 var ShellSpawn : Transform; // where the bullet shelll is going to be instantiated from
 public var ShootAnim : Animation; // the shooting animation
 public var ReloadAnim : Animation; // the reload animation (magazine is not empty)
 var ReloadEmptyAnim :Animation; // the reload animation (magazine is empty)
 public var IdleAnim : Animation; // the idle animation
 public var canShoot : boolean = true; // can the player shoot?
 public var canReload : boolean = false; // can the player reload?
 public var canAim : boolean = true; // can the player aim down sights?
 
 var clip = 30; // number of bullets in the magazine
 var ammoLeft = 320; // maximum ammo you can carry 
 var TimeBetweenShots : float = 0.09; // controlls the fire rate
 var timestamp : float;
 
 var Effect : Transform; // the effect that will be displayed at the bullet's hit position (like: bullet holes, blood, etc..)
 var TheDammage = 46; // the damage of a single bullet hit
 var AimSound : AudioSource; //aim audio source 
 
 var maxBulletSpreadAngle : float = 1.5f; // the bullet spread angle
 public var IsAiming : boolean = false; // is the player aiming?
 
 var MagazineDisplay : UnityEngine.UI.Text; // mag HUD
 var AmmoLeftDisplay : UnityEngine.UI.Text; // Ammo left HUD
 
 //Muzzle Flash Variables
 var MuzzleFlash : Renderer; // muzzle flash texture
 var MuzzleLight : Light; // point light
 
 var SmokePuff : GameObject; // smoke particle
 var SmokeSpawn : Transform; // position of the smoke particle
 
 public var FireSound : AudioClip; // audio file of a single shot
 var SoundSpawn: AudioSource; // audio source for the FireSound file
 
 var FullAuto : boolean = true; // boolean checking for full auto or semi auto
 
 var IsReloading : boolean = false; // is the player reloading?
 var finishReload : boolean = false; // player finished reloading?
 
 
 function Start () {
 
 MuzzleFlash.enabled = false; // disable the muzzle flash texture on start
 MuzzleLight.enabled = false; // disable the point light on start
 
 SoundSpawn = GetComponent.<AudioSource>();
 }
 
 function Update () {
    
    var hit : RaycastHit;
     var ray : Ray = Camera.main.ScreenPointToRay(Vector3(Screen.width*2, Screen.height*2, 0));
    
    var fireDirection : Vector3 = transform.forward;
    
    var fireRotation : Quaternion = Quaternion.LookRotation(fireDirection);
    
    var randomRotation : Quaternion = Random.rotation;
    
    fireRotation = Quaternion.RotateTowards(fireRotation,randomRotation,Random.Range(0.0f,maxBulletSpreadAngle));
    
    
    if(Input.GetButton("Fire1") && clip > 0 && Time.time >= timestamp && canShoot == true && FullAuto == true){
        SoundSpawn.PlayOneShot(FireSound, 0.7F);
        clip -= 1;
        Fire();
 if (Physics.Raycast (transform.position,fireRotation*Vector3.forward, hit, 100))
         {
             Debug.DrawLine (transform.position, hit.point, Color.green);
             var particleClone = Instantiate(Effect, hit.point, Quaternion.LookRotation(hit.normal));
             Destroy(particleClone.gameObject, 2);
             hit.transform.SendMessage("ApplyDammage", TheDammage, SendMessageOptions.DontRequireReceiver);
         }
     }
    
    if(Input.GetButtonDown("Reload") && clip != 0 && ammoLeft != 0 && canReload == true && IsReloading == false ){
        canAim = false;
        canShoot = false;
        Reload();
  }     
    
 
    if(clip == 0 && ammoLeft > 0 && IsReloading == false){
       ReloadSound.Play();
       ReloadEmptyAnim.Play("reload_empty");
       canAim = false;
       canShoot = false;
       AutoReload();
 
 
    }
       
    if(clip != 30 && ammoLeft != 0){
     canReload = true;
     
    }
       
 
    if(Input.GetButton("Fire1") && clip == 0 && ammoLeft == 0 && !ReloadAnim.IsPlaying("reload")){
       DryGun();
     }
 
 
 if(Input.GetButtonDown("FireMode") && FullAuto == true){
    
    FullAuto = false;
    FireModeSound.Play();
    
       }else if(Input.GetButtonDown("FireMode") && FullAuto == false){
    FullAuto = true;
    FireModeSound.Play();   
       }
       
       
       if(Input.GetButtonDown("Fire1") && clip > 0 && Time.time >= timestamp && canShoot == true && FullAuto == false){
        SoundSpawn.PlayOneShot(FireSound, 0.7F);
        clip -= 1;
        Fire();
 if (Physics.Raycast (transform.position,fireRotation*Vector3.forward, hit, 100))
         {
             Debug.DrawLine (transform.position, hit.point, Color.green);
             particleClone = Instantiate(Effect, hit.point, Quaternion.LookRotation(hit.normal));
             Destroy(particleClone.gameObject, 2);
             hit.transform.SendMessage("ApplyDammage", TheDammage, SendMessageOptions.DontRequireReceiver);
         }
     }
 
 
 MagazineDisplay.text = "" + clip;{
 AmmoLeftDisplay.text = " /" + ammoLeft;
 }
 
 
  
  
 
  }
 
                                                                                                                                                                                                         
 function Fire() {
         
  ShootAnim.Play("shoot");
 timestamp = Time.time + TimeBetweenShots;
          if(ShootAnim.IsPlaying("shoot"))
         ShootAnim.Rewind("shoot");
         
 }
 
 function Reload() {
 
 IsReloading = true;
 
 canAim = false;
 
 canReload = true;
 
 ReloadAnim.Play("reload_full");
 
 ReloadSound.Play();
    
 yield WaitForSeconds(3.7);
 
 var totalAmmo = clip + ammoLeft;
       if(totalAmmo <= 30){
           clip = totalAmmo;
           ammoLeft = 0;
       }else{
           var shotsFired = 30 - clip;
           clip = 30;
           ammoLeft -= shotsFired;
       }
 
 canShoot = true;             
 
 canReload = false;
 
 canAim = true;
 
 IsReloading = false;
 
 finishReload = true;
 
 yield WaitForSeconds(0.1);
 
 finishReload = false;
 }
 
 
 function AutoReload() {
 
 IsReloading = true;
 
 yield WaitForSeconds(3.7);
 
 totalAmmo = clip + ammoLeft;
       if(totalAmmo <= 30){
           clip = totalAmmo;
           ammoLeft = 0;
 
        }else{
            shotsFired = 30 - clip;
           clip = 30;
           ammoLeft -= shotsFired;
 
       }
 
 canShoot = true;   
 
 canAim = true;
 
 canReload = false;
 
 IsReloading = false;
 
 finishReload = true;
 
 yield WaitForSeconds(0.1);
 
 finishReload = false;
 
 }
 
 function DryGun(){
 
 DrySound.Play();
 
 }

Any Suggestions?