The selection of 12 gauge semi auto shotguns is mind boggling. Do you need 3-1/2" capability? What are you going to be hunting? For any Federal migratory species 3 is all you are allowed capacity wise. Everyone can now tell you why one like theirs is "best", but truth be known one from any of the major manufacturers will do the job, and you should be able to get almost any used under $800. IMO a good used gun beats hell out of a new cheap gun.
What could have happened... did.