Bullet not destroying on collision

for some reaon my bullets are not doing any damage, and i know they are hitting becaause i put a rigid body on my target and i can tell it gets hit
here is my bullet code

function Start()
{
Destroy(gameObject, 5);
}
var dmg:float = 20;

function OnTriggerEnter(hit:Collider){
if(hit.tag == "Enemy"){
hit.transform.SendMessage("Damage",dmg);
}

}

here is my ai code

var target : Transform; //the enemy’s target
var moveSpeed = 3; //move speed
var rotationSpeed = 3; //speed of turning

var myTransform : Transform; //current transform data of this enemy

function Awake()
{
myTransform = transform; //cache transform data for easy access/preformance
}
function Update () {
//rotate to look at the player
myTransform.rotation = Quaternion.Slerp(myTransform.rotation,
Quaternion.LookRotation(target.position - myTransform.position), rotationSpeed*Time.deltaTime);

//move towards the player
myTransform.position += myTransform.forward * moveSpeed * Time.deltaTime;
}

var health:float = 1;

function Damage(dmg:float){
health -= dmg;
}
if(health <=0){
Destroy (gameObject);
}

Add this to whatever code is attached to your bullet.

This tells whatever object it’s attached to to destroy itself on contact with anything.

private void OnCollisionEnter(Collision collision)
    {
        Destroy(gameObject);
    }