My Brother in law had the 212 and it was around 1.5 MOA with the 2 3/4" Hornady SST's at 100 yards with a 3x9 scope benched. The guy he bought it from said those were the best in it. Maybe try out some of those.
Another thing that the previous owner stressed was that you had to keep it clean and do it after every 5 rounds! Apparently, the rifling gets filled with plastic fouling very quickly and must be removed or accuracy really falls off. If you don't have any cleaner that is specific for shotguns and plastic fouling, you need to grab some. Not many other cleaners can get that out very well.