In 5th edition I considered the Automatics Skill a bit too generic and overshadowed all other alternatives when it came to firearms so I House Ruled that Longarms covered all weapons you held with two hands while bracing it against your shoulder (no matter firing mode, including, but not limited to, SMGs - at least as long as you held them with two hands braced against your shoulder, think 'SWAT'-style). And that Pistols covered all weapons you held with one hand (no matter firing mode, including, but not limited to, SMGs that you held with one hand or even dual wielded, think 'gangsta'-style).
This caused a lot of deliberate overlap between Longarms and Automatics (for example Assault Rifles) as well as Pistols and Automatics (for example Machine pistols). And in the case of SMGs, depending on how you wielded it, even a potential overlap between Longarms, Pistols and Automatics.
But I would personally be hard pressed to count Remmington Roomsweeper as anything else but linked to the Pistol skill. It is basically a Heavy Pistol, after all....
