The X-frame rubber Hogues made for OEM use for S&W's .460 & .500 Magnum revolvers will fit the K/L and N-frames as well as the designed for X-frames. They are available for ~$35 from S&W Accessories - and make a great adjunct fot recoil control, as they insulate (cover) the backstrap on the round butt grip frames. In doing so, they make my 629's a lot more comfortable to shoot real Magnums from. The side offshoot - and reason I mention them - is they also are the largest grips I own. To evaluate their suitability, find a local dealer, etc, who stocks either a .460 Magnum or .500 S&W and ask to hold same - that's the grip.
Stainz
PS I liked the JM grips so much on my 625JM that I bought some for my 627 Pro - and I love them there!