There is an interesting discussion on Remington 870 Forum. jdinny posted pics of his Remington 870 with ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock:

ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock

ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock

ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock

ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock

ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock

ATI AR-15 Scorpion Recoil Pistol grip on Mesa Tactical LEO Stock