hello all i'm the recent second owner of an M4S90 that came with an installed 4-notch improved cylinder (?) 'ok for steel shot' choke. i have a benelli threaded 4-notch 'pattern master' choke and an older polychoke II ("its like having a nine barreled shotgun") that i would like to use on the gun. i don't have a lot of either experience or knowledge in this area and perhaps i'm being a little too cautious, but i am concerned that just because the threads 'fit' may not mean that these chokes can be applied to this gun. can anyone out there give me some assurance that using these chokes in an M4S90 will not damage the gun or cause some injury to its user or others? thanks john s.