Unity3D: A shooting routine - Source: http://wiki.dreamsteep.com/Unity3d

MachineGun.js

//My First Unity tool , it will shooot stuff  , Keith Legg Jan 24
//to use drag this script to the main camera  (or a vehicle's transform node ) , then drag a prefab to the bullet channel on the right 
//be sure to adjust force/rate of fire so bullets dont hit each other when instantiated (example: higher force = slower the rate)
//space bar will fire gun on positive Z axis 

//for a good default try 1000 force , 3 shots , and .1 second delay 

var bullet: Transform;
var shootForce: float  ;
var fullauto: boolean  = true;
var number_shots: int ;
var delay_shots: float ;

//"machine gun"
function shootfullauto () {
		  for (a=0;a<=number_shots;a++){
            var instancedbullet =Instantiate( bullet ,transform.position,Quaternion.identity);
	         instancedbullet.rigidbody.AddForce(transform.forward * shootForce);
             yield WaitForSeconds(delay_shots);   
          }

}

function Update () {
   var timer : float = 0.0;
	 if (!fullauto){
   
      if(Input.GetButtonDown("Jump")  ) 
     {  
       var instancebullet =Instantiate( bullet ,transform.position,Quaternion.identity);
	   instancebullet.rigidbody.AddForce(transform.forward * shootForce);
     }
	 
  }

   if (fullauto){
	
	   if(Input.GetButtonDown("Jump")  ) 
       {
          shootfullauto();

	    }
    }
}