I have the B-square mount and I use it for my model 41 made in Monson MA. It works great for load testing, but is a little bulky for hunting. I got the mount when I purchased the pistol. I think Leupold makes a set of rings that clamp onto the rib which would be the route I would go if I had to start from scratch. Several other manufactures also might make a similiar set up. While testing ammo for my new manufactured 722, I had to remove a little of the aluminum on the clamps to fit the rib.