The paintball loader is typically attached via an elbow.
A paintball loader, which is also sometimes referred to as the hopper, is the part of the paintball marker that holds the paintballs. It loads them into the breach of the paintball marker so they can be fired. Paintball markers have an open feed tube on the top of the marker, through which paintballs will fall into the breach from which they can then be fired; the loader attaches here. Though Viewloader makes several different loader models, you should be able to install all of them in the same way.
1. Examine your paintball marker. Your paintball marker may be a side loader, in which case the feed tube will be offset to one side of the marker or the other. You may also have a vertical loader, in which case the feed tube will come directly out of the top of the marker.
2. Insert the elbow onto the feed tube of your paintball marker. If your paintball marker is a side loader then your elbow should have an angle. If it is a vertical loader then your elbow should have no angle. Some vertical loaders do not need an elbow so the loader can be inserted directly into the vertical tube.
3. Insert the loader into the other side of the elbow. Make sure the loader is aligned with the marker, so it presents the smallest possible profile to an opponent shooting at you.
4. Tighten both sides of the elbow by turning the screws on either side of the elbow. Both screws should have ends that can be tightened by hand.