Instantiate bullet in time interval for "rifle".

Help me here guys, please...

I made this script for my cannon:

 @script ExecuteInEditMode()
 
 var bulletPrefab: Transform ;
 var bulletSpeed: float = 60;
 var buttonX: int = 0;
 var buttonY: int = 0;
 var rifle: boolean = false;
 var nextShotTime : float = 0.0;
 var timeBetweenShots : float = 2.0;
 
 function Update()
 {
  if(Input.GetKeyDown(KeyCode.M))
  {
  if(rifle)
  {
  rifle = false;
  }
  else
  {
  rifle = true;
  }
  }
  if (Input.GetButtonDown("Fire1"))
  {
  if(rifle)
  {
  Shoot();
  }
  else
  {
  if (nextShotTime <= Time.time)
           {
               Shoot();
               nextShotTime = Time.time + timeBetweenShots;
           } 
  } 
  
  }
 }
 
 function Shoot()
 {
     var shoot = Instantiate(bulletPrefab,GameObject.Find("Spawn").transform.position,GameObject.Find("Spawn").transform.rotation);
  shoot.rigidbody.AddForce(GameObject.Find("Spawn").transform.forward * bulletSpeed);
 }
 
 function OnGUI()
 {
 if(rifle)
  {
  GUI.Box (Rect ( 10,40,150,30), "rifle");
  }
  else
  {
  }
 }

For the normal mode it is doing what i want it to do, shooting the bullet only from time to time (2 seconds in this case) even if i press the fire button more than that... Now... How do I get my rifle mode to work.. So far it only makes it possible to shoot without the time interval set but i want it to do the opposite, instantiate automatically the prefab from time to time, in this case, every 0.02 seconds or so... Can you help guys? Thanks a lot.