Mark, the bipod set up I have is the Versa-PodŽ Model 51 7-9" Bipod Short Prone Bipod with Pan/Tilt and Cant Friction Lock Model.
http://www.versapod.com/m_h/sporting...oducts_pr.html
The grip that I use is the Versa-Pod Vertical Foregrip Adapter
Model (150-618). http://www.versapod.com/m_h/sporting...ducts_acc.html.
The reason I went with this set-up is because I wanted to take some of the weight from the front of the weapon. It was a little front heavy with the Harris Bipod I had. The Versa-Pod that I have pretty much does everything as far as swivels, tilts, and pans and the legs are spring loaded like the Harris. I also like the location of the Versa-pod becasue it is easier to manuever my AR around when I am shooting from the prone position. The further out you have it, the more stability you have, but the closer to the magazine you have it, it is more manuverable.
As far as the sling, I actually have the front swivel attachment near where the grip-pod is. I just put it like that for the pictures to get the sling out of the way a little more. I don't have any problems with the swivel type attachment. It does tend to rotate some, but once I have it on, it doesn't bother me.

