WR, yup,what Kilgor said, except...
How the piece swings is a very personal choice kinda thing. For most clay sports, I'd like a more muzzle heavy swing than I would on a hunting shotgun, especially one for woodcock, grouse, quail,etc.OTOH, most clays guns, properly choked, do well as dove guns, or on late season pheasants.
I countered the lighter front end of my bird 870 with its' 21" bbl by hogging out some wood to keep the balance point between the hands.The shotguns with LC bbls might need the same treatment in my hands, if not yours.