I have a set for the S&W J-frame round butt. Mine are the smaller boot grip type with an open backstrap. They tend to hurt my arthritic right thumb's base knuckle when I fire anything more than a very mild .32 round. The back of the speed loader relief cutout area has a sharp edge that hurts when the revolver recoils. That is just in my case perhaps. If I were to buy another for that application, I would get the larger overmoulded type. That said, the only other complaint would be the cost. With my aged eyes, they are a great help and they have some real tactical advantages over conventional sights. They are expensive but well worth it if you have the $ in my opinion...