Are you placing the rest under the hinge? They shoot best from a rest that way, but you can work with the forend to get them to not be so sensitive to rest palcement. See if it will shoot a nice group cool without the forend on it, but put the forend on just to reload, then take it back off to shoot. If it shoots a good group cool without the forend, then you need to work with the forend pressure.
Tim