I made mine own. Got to use the stupid golf clubs my son drug home from some place. Cut them off, drilled a hole in the shafts just below the grips then installed a bolt with a wing nut. The tightness of the wing nut keeps the spread easy to manage. Also the grips don't cause any damage to the rifle stock.
Second set were the first ones I made. I ripped some cedar in 3/4" strips on my table saw then drilled the hole for the bolt and wing nut. I lined the Y where the stock sets with that tape they used between your pickup bed rail and the cap. I have the stuff to modify this set into a tri pod but havn't got to it yet.

Al