I would be interested in comments on the legality of a non-attachable shoulder stock. I have such a device. It's a wire stock, the end of which is curved to conform to the rear strap of a Ruger Mk II. The gripping hand is placed through the stock, holding the stock firmly against the rear strap. I suppose one could more accurately describe this as a "steady rest" rather than a "stock", as it is immediately separated from the pistol when one releases their grip on the butt.