My RayCast isn't facing forward

Currently there is a script which references the position of an invisible GameObject at the front of the muzzle, and draws a ray from its position. It’s supposed to draw it forward, but for some reason when I execute my code:

private GameObject muzzle;

void Start () {
        muzzle = GameObject.Find("pistol_BulletSpawner");
}

void Update {
        Debug.DrawLine(muzzle.transform.position, 
                       muzzle.transform.TransformDirection(Vector3.forward), Color.blue);

}

It points down and to the right, like this:

Kind of solved my own issue. Apparently Debug.DrawLine doesn’t operate in the same way that Debug.DrawRay does - which seems obvious, but I didn’t think of it at the time. That being said, I’ve found that using ‘.TransformDirection(Vector3.forward)’ with Debug.DrawRay points to the right, rather than forward. I had to use Vector3.left instead, which seems to work - still not sure what’s causing that.