FPS Gun Accuracy & Bullet Tracers

Hi I was wondering if anyone had an idea on how to make a gun less accurate depending on how many bursts or how long the user holds down their button. What I'd like to do is have each gun have a variable with Accuracy, then based on that the longer that they hold the "trigger" the lower the accuracy goes thus making the aim of the gun jump or spray slightly. I'm also wondering if anyone has any idea on how to, instead of bullets have what appear to be "bullet tracers" when shooting, so it looks like streaks of color projecting towards the enemy.

 var force = 200.0;
var range = 100.0;
/*
var bulletsPerClip:float = 20;
var bulletsLeft:int = 0;
var numClips = 5;
*/
var fireRate = 0.1;
var gunshot:AudioClip;
var muzzleFlash:Renderer;
private var nextFireTime = 0.0;
private var m_LastFrameShot = -1;

function Start(){
        //bulletsLeft = bulletsPerClip;
        muzzleFlash.enabled = false;
}

function Update(){
        if(Input.GetButton("Fire1")){
            Fire();
        }
}

function LateUpdate(){

    if(muzzleFlash){
        if(m_LastFrameShot == Time.frameCount){
            muzzleFlash.transform.localRotation = Quaternion.AngleAxis(Random.value*360,Vector3.forward);
            muzzleFlash.enabled = true;

        } else {
            muzzleFlash.enabled = false;
        }
    }
}

function Fire(){

    if(Time.time - fireRate > nextFireTime){

        nextFireTime = Time.time - Time.deltaTime;

        while(nextFireTime < Time.time){
            FireShot();
            nextFireTime += fireRate;
        }
    }

}

function FireShot(){
audio.PlayOneShot(gunshot);

    var direction = transform.TransformDirection(Vector3.forward);
    var hit : RaycastHit;

    if (Physics.Raycast (transform.position, direction, hit, range))
    {
        // Apply a force to the rigidbody we hit
        if (hit.rigidbody){
                hit.rigidbody.AddForceAtPosition(direction * force,hit.point);
        }


    }
    BroadcastMessage ("BulletHit", hit);
    m_LastFrameShot = Time.frameCount;
    enabled = true;
}

I've actually been working on a re-useable weapon system for FPS', so I'll post what I've been using for weapon accuracy:

    function SprayDirection() {
var vx = (1 - 2 * Random.value) * shotSpread;
var vy = (1 - 2 * Random.value) * shotSpread;
var vz = 1.0;
return transform.TransformDirection(Vector3(vx,vy,vz));

}

Basically all you would have to do is change the direction of your shot raycast from

    var direction = transform.TransformDirection(Vector3.forward);

to

    var direction = SprayDirection();

And add to the value of "shotSpread" every time you fire a bullet and return it to normal when you stop.


As far as implementing muzzle climb (making the gun slowly aim higher as you fire), all that you would need to do would be to modify the standard "MouseLook" script a little.

            // Read the mouse input axis
        rotationX += Input.GetAxis("Mouse X") * sensitivityX/60*cmra.camera.fieldOfView;
        rotationY += (Input.GetAxis("Mouse Y") * sensitivityY/60*cmra.camera.fieldOfView + offsetY);

Basically "offsetY" rotates the camera upwards, so if you add to "offsetY" whenever you fire a bullet the gun will aim higher as you fire. Just get a hold of the camera (mainCam in my script) and add to the variable

    mainCam.GetComponent("MouseLook").offsetY = kickbackAngle;

P.S. I'm sorry if this is too much but it's exciting to see a question that is exactly what I'm working on.