duck

var projectile : Rigidbody;
var speed = 50;
var fireRate = 0.5;
private var nextFire = 0.0;

function Update()
{
    if( Input.GetButton( "Fire1" ) && Time.time > nextFire) {

        nextFire = Time.time + fireRate;
        var instantiatedProjectile : Rigidbody = Instantiate(projectile, transform.position, transform.rotation );
        instantiatedProjectile.velocity = transform.TransformDirection( Vector3( 0, 0, speed ) );
        Physics.IgnoreCollision( instantiatedProjectile. collider, transform.root.collider );

    }
}