I have a pistol grip only on my Remington 870. It is a Blackhawk Knoxx breacher grip. It is NOT just a pistol grip. There is an internal recoil-reducing system INSIDE the grip that all but eliminates recoil. I use 3 inch magnum and recoil is very mild. I like the pistol grip for home defense because it makes the gun much more manuverable if I need to go room-to-room. Watch this:
http://www.youtube.com/watch?v=SM6-FdS0idw