3rd Axis goes rapid once held down. How do I fix this?

I been using this Javascript for Raycast styled shooting. I also added controller support to the game but when I hold down LT on the Xbox 360 controller (Which is the button I set to for firing the gun) instead of the gun firing one bullet each time I press down LT, the gun just fires rapidly like a machine gun when I need it to fire like how handguns work in games. How do I fix this problem so the gun only shoots one bullet each time I press down LT?

Incase you need to see the Raycast shooting script, here it is:

Code (csharp):

1. #pragma strict
2.  
3. var Effect : Transform;
4. var TheDammage = 100;
5.  
6. function Update () {
7.  
8.     var hit : RaycastHit;
9.     var ray : Ray = Camera.main.ScreenPointToRay(Vector3(Screen.width*0.5, Screen.height*0.5, 0));
10.  
11.     if (Input.GetMouseButtonDown(0) || Input.GetAxis("Xbox360ControllerTriggers"))
12.     {
13.         if (Physics.Raycast (ray, hit, 100))
14.         {
15.             var particleClone = Instantiate(Effect, hit.point, Quaternion.LookRotation(hit.normal));
16.             Destroy(particleClone.gameObject, 2);
17.             hit.transform.SendMessage("ApplyDammage", TheDammage, SendMessageOptions.DontRequireReceiver);
18.             audio.Play();
19.         }
20.     }
21.  
22. }

 

Okay thanks but do you have a solution to my question?

 

you put a timer.. and make a rate of fire... you say if(timer >= 0.4 seconds (or whatever time)) canshoot = true .. if (canshoot == true) then Shoot, canshoot = false, and timer = 0

or something like that

without a timer, yeah.. youre saying it Shoots as long as button is held, every frame it shoots.