The Sherburn federal WMA near Big Lake, MN. has been all non toxic shot for years.
Although it has never happened to me, the federal wardens who work the unit have a reputation for being hard-nosed and quick to write citations, that are a lot more expensive than those written by state agents.
Under the careful management of the federales, the quality of the hunting there is a shadow of what it was in the 70s and 80s, but, it is good enough for taking my little boy and our old setter dog for a run on a Sunday morning. I keep an old Mossberg 500 and a box of steel 6s around for those days.
If I'm doing something wrong and the feds want the Mossberg, they can have it.
Best,
Ted