As already mentioned, AS is a bad, bad choice. They're not particularly accurate at range unless you put a lot of money work upgrading them. A $50 pellet / BB gun from Cdn Tire or other outdoors store (even pistols) will be much, much better than any AS gun for that purpose.
As for a full auto SMG, the only auto SMG BB gun on the market that I know of the is Drodz. It's an electronically controlled CO2 gun which will fire semi auto or bursts.