That will depend on whether the choke tube is rated for steel shot or not.
If it was made to shoot steel shot and has interchangeable chokes.
No.
As long as the barrel was made after 1950 and does NOT have a full choke, you will be able to shoot steel #2 or smaller.
NOT RECOMMENDED unless you are in a life or death situation.
Most ARE shot from full choke- or even Extra Full Choke.
Yes. Please note that is lead shot SIZE BB, and not the steel balls shot by air rifles.
Depends on the load and what the maker of the choke/shotgun say.
No.
You can use steel shot with a choke anywhere from cylinder to modified, i wouldn't recommend using steel with a improved modified or a full choke.
I see no reason that you cannot.The steel shot sould work fine in your ranger model 120 shotgun.
Check the owner's manual, or check with Mossberg customer service. Unless the choke is rated by the maker for steel shot, not good to do.