Projectiles follow camera forward instead of a logical path

I use the following script and attach it to ARCamera. If I fire the projectile facing south, then turn 180 degress facing north, the projectile follows the center of the camera and continues it's path north... Any ideas?

	GameObject prefab;
	Rigidbody rb;

	// Use this for initialization
	void Start ()
	{
		prefab = Resources.Load ("projectile") as GameObject;
	}
	
	// Update is called once per frame
	void Update ()
	{
		if (Input.GetMouseButtonDown (0)) {
			GameObject projectile = Instantiate (prefab) as GameObject;
			projectile.transform.position = transform.position + Camera.main.transform.forward * 2;
			rb = projectile.GetComponent<Rigidbody> ();
			rb.velocity = Camera.main.transform.forward * 40;
		}
	}

Another issue I am seeing is the partical effects that trail off the projectile are following the physics of the camera, not the projectile. So if I shoot straight, without gravity, and shake the camera, the partical effects reflect the camera movement...