Want to shoot to make an explosion

Hey this is simple and I am confused when I want to shoot I want an explosion coming out of the barrel. "Spawnpoint" actually. Here is my SHOOT script

var projectile : Rigidbody;
var speed = 10;

function Update () {

    if (Input.GetButtonDown("Fire1")) {

    var clone : Rigidbody;
    clone = Instantiate(projectile, transform.position, transform.rotation);

    clone.velocity = transform.TransformDirection (Vector3.forward * speed);

    }
}

You just Instantiate a particle emitter. Like so:

var explosion : Transform;

function Update ()
{
    if(Input.GetButtonDown("Fire1"))  
    {
    Instantiate(explosion,gameObject.Find("Spawnpoint").transform.position,Quaternion.identity);
    }
}

Okay here is what you can do this:

var projectile : Transform;

var speed = (whatever you want);

var explosion : Transform;

function Update () {

if (Input.GetButtonDown("Fire1")) 

{

var clone = Instantiate(projectile, transform.Find("Spawnpoint").transform.position, Quaternion.identity);

var Exp = Instantiate(explosion, transform.Find("Spawnpoint").transform.position, Quaternion.identity);

clone.rigidbody.Addforce(transform.forward * speed); } }