You can fire any semi-automatic weapon or pistol by the technique known as bump firing, and that could be used to cover someone's retreat if need be.
The art of bump firing takes some practice if you don't mind wasting ammo, or you could get your AK or AR-15 equipped with this special stock. Then everybody can own an automatic, legally, too.
Incredible Bump Fire! - YouTube
Bump Fire Everyone trying the new slide fire stock. - YouTube