Weird Output from AngleAxis

Quaternion.AngleAxis is giving me weird output/rotation when Im using it to set the rotation of my player object to look at my mouse in a 2d X/Y Plane.

Here's a snippet of where the problem is believed to be

   mouseDir = Camera.main.ScreenToWorldPoint(Input.mousePosition) - child.transform.position;
   shootAngle = Mathf.Atan2(mouseDir.y, mouseDir.x) * Mathf.Rad2Deg;
   child.transform.rotation = Quaternion.AngleAxis (shootAngle, Vector3.forward);

child.transform.rotation.z (the z axis) of the object is returning 0, which is perfect, but shootAngle is returning 6, this is making rotations of instantiated offset.

Here's an image to represent my problem.

As you can see when my cursor is exactly horizontal to the player, the player's rotation is at 0, but the AngleAxis(shootAngle) returns me a 6 degrees as the rotation, shouldn't it be at 0 as well? When I instantiate objects using the player's rotation is shoots the object 6 degrees.