As the rear stock of the DW is not sloped, I was having trouble changing elevation when shooting from the bench at our rifle range. This was exacerbated by my old, arthritic hands. Tried adding shims to the rear sand bag but that only resulted in a minor improvement. When I searched the internet, I found the Adjustable Bag Rider (ABR). Talked with David at ABR and sent pictures of the DW. David suggested the appropriate ABR with an angled base. Got it last week. Install on the bottom rear picatinny rail and went to the range. The ABR made a great difference. Now with my left hand, I can just turn the wheel to make smooth and precise adjustments in elevation while not “fighting” with the rear sand bag. Vertical adjustmentis approximately 1 inch. Now my hand doesn’t hurt and no more l frustration with the rear bag. '