I'm not sure but I do know that if you rest the gun on the butt and shoot, it will impact differently if you rest just the forend BUT also try and provide the same pressure with each shot. The gun will recoil differently based on how you rest the gun or support hand. This probably isn't clear but you have to find that consistent hold.
BullElk Hunter (Gerry)HHI #2933
And I heard the voice of the Lord saying, whom shall I send and who will go for us? And I said: Here am I, send me!(Is. 6:8)