There are a large number of states that allow the use of the 8 gauge shotgun. The real beef in mst areas is with the Federal law not allowing its use for Migratory birds.
I was able to get the state of Arizona to allow the use of the 8 gauge for all large game except Bison and for use on preditors and birds that are not migratory.
I believe it is legal in most many states to hunt with an 8;gauge.