Seeing two barrels, while the gun is mounted into the shoulder and both eyes are open, is not ocular cross dominance! It is called natural diplopia.The shooter sees two barrel imagines. One of the images represents the real barrel and the other one represents the ghost barrel. This phenomenon occurs because the object we're seeing (the gun) is too close to our eyes compared to the distance of our closest focal point. The closest focal point is where the two eye axises intersect at the closest point from our eyes. If the object is closer than this focal point then the shooter perceives both images from each eye.If you close one eye the ghost image disappears.