On the rear of the Harris bipod there is a provision for attaching a sling swivel (if you mounted your bipod backwards it would be on the front- a good time to turn it around would be now). Although it’s there, and being there it seems like it must be an acceptable location to mount a sling, there are a couple significant disadvantages to using it.
The first big disadvantage occurs when using the sling to carry the rifle muzzle up. The best place to carry a rifle is in the hands, but sometimes we end up using the sling. Normally in “American carry” (muzzle up on strong side) the weight of the rifle is distributed over the length of the sling that is on the shoulder. When the Harris bipod is used as a sling stud, a large part of that weight is borne by a small piece of aluminum pressing into your shoulder.
When mounted conventionally on a swivel stud, the sling carries the weight. The bipod does contact the body, but it’s incidental and not supporting the weight. In fact, I had never realized before that it touches.
The second disadvantage occurs when you need to use your sling as a shooting aid. A normal forward mounting point, which is typically a swivel stud mounted in the stock or a flush cup, keeps the sling mounted close to the stock. This sling-to-stock junction can be used as a handstop, which makes for consistency (good consistency makes for greater opportunities for precision and accuracy).
The Harris bipod, being shaped like a brick, does not make for a comfortable handstop.
Other than being useful as a handstop, the sling being closer to the stock also allows the sling to trap the support hand under it when slung up. As I point out here, this allows the support hand to relax instead of having to grip the forend, it increases the perception of stability, and it affects the leverage of the sling favorably. This is only true when wrapping the support hand, which I recommend (click the ling, read, try both ways and see for yourself).
Many modern rifles come with two front swivel studs. I suggest making use of the rear of the two studs for mounting your sling (duh). Two of my rifles have accessory rails, one an Anschutz and one a Freeland. This affords me a good opportunity to mount a swivel stud behind the bipod. If you rifle is not conveniently equipped with a mounting spot for a sling and a bipod, and you are inclined to use a bipod, I suggest installing an extra mounting point. Don’t give in to substandard mounting options just because they’re there.