Shallow rifling has been used in shot bbls for the purpose of spinning the charge for greater dispersal. Straight grooves have likewise been used in an attempt to insure against any spin in attempts to increase the pattern. Quite often though these have been put in only at the muzzle.
Rifled choke has of course been used for a ball/shot gun, but generally the spin induced to the shot charge is said to produce more open paterns than the same choke would without the rifling. Never owned one so can only state what I have read on them.
