Play sound when out of ammo

I want it so when my player has 0 bullets in clip to play audio "ImOut" but I don't have to working, what I have so far is when bulletsinclip = 0, it doesn't play the sound, it only plays the sound when I reload. The reason I have 2 scripts is because on my Gun script I have the gun fire sound, and on my ImOut gameobject I have the ImOut audio source

my scripts

Gun Script

 #pragma strict
 
 var damage:float = 38;
 var range = 100.0;
 var force = 10.0;
 var muzzleFlash : Renderer;
 var muzzleLight : Light;
 
 var UMPMenu: GUIStyle;
 var ReloadMenu: GUIStyle;
 
 static var ImOut = false;
 
 var ReloadWarning = false;
 
 var cameraTransform: Transform;
 
 static var _UMPCanReload = false;
 
 var clipSize: int = 25;
 var bulletsInClip = 25;
 var bulletsLeft = 75;
 var allowfire : boolean = true;
 
 function Start (){
 muzzleFlash.enabled = false;
 muzzleLight.enabled = false;
 }
 
 function Update () {
 if(Input.GetMouseButton(0)){
 if(bulletsInClip >= 1){
 if(allowfire == true){
 fire();
 }
 }
 }
 if(bulletsInClip == 0){
 ImOut = true;
 }
 
 if (Input.GetKeyDown (KeyCode.R)){
 if(bulletsInClip == 0){
 if(bulletsLeft >= 25){
 Reload();
 }
 }
 }
 if(bulletsInClip == 0){
 if(bulletsLeft >= 25){
 ReloadWarning = true;
 }
 } else {
 ReloadWarning = false;
 }
 if(bulletsInClip == 0){
 if(bulletsLeft >= 25){
 _UMPCanReload = true;
 }
 } else {
 _UMPCanReload = false;
 }
 }
 
 function OnGUI() {
 if(ReloadWarning == true){
 GUI.Label (Rect (Screen.width / 2.2, Screen.height / 2.5, 200, 200), "Press R to reload.", ReloadMenu);
 }
 GUI.Label (Rect (10, 650, 350, 350), "UMP .45", UMPMenu);
 GUI.Label (Rect (10, 700, 350, 350), bulletsInClip + " / " + bulletsLeft, UMPMenu);
 }
 
 function fire(){
 allowfire = false;
 audio.Play();
 bulletsInClip--;
         
 var direction = transform.TransformDirection(Vector3.forward);
 var hit : RaycastHit;
 
 // Did we hit anything?
 if (Physics.Raycast (cameraTransform.position, cameraTransform.forward, hit)) {
 
 Debug.DrawRay(transform.position, direction * range);
 // Apply a force to the rigidbody we hit
 if (hit.rigidbody)
 hit.rigidbody.AddForceAtPosition(force * direction, hit.point);
 hit.collider.SendMessageUpwards("ApplyDamage", damage, SendMessageOptions.DontRequireReceiver);
 }
 
 muzzleFlash.renderer.enabled = true;
 muzzleLight.enabled = true;
 yield WaitForSeconds (0.04);
 muzzleFlash.renderer.enabled = false;
 muzzleLight.enabled = false;
 
 
 yield WaitForSeconds(0.2);
 allowfire = true;
 }
 
 function OnTriggerEnter(hit:Collider){
 if(hit.tag == "Enemy"){
 hit.transform.SendMessage("Damage",damage);
 }
 }
 
 function Reload(){
 allowfire = false;
 yield WaitForSeconds (1);
 bulletsInClip = clipSize;
 bulletsLeft = (bulletsLeft - clipSize);
 yield WaitForSeconds (0.3);
 allowfire = true;
 }

UMPImOut script

 function Update () {
 if(UMP.ImOut == true){
 audio.Play();
 UMP.ImOut = false;
 }
 }