In my Rogue trader group, the Navigator has decided that since his Ballistics Skill is so low, he wishes to focus on flamethrowers (specifically hand flamers, as he does not have Basic Weapon Training (Universal) yet.) He knows that getting an auto-pistol and using suppressing fire would help greatly, but I can't fault him for wanting to cause damage and mayhem. Flamers do not need a roll for Ballistics Skill, but come in pistol, basic and heavy varieties, and so he wishes to focus on them.
However, that got me thinking, are there other ranged weapons in Rogue Trader (and Dark Heresy) that do not require a Ballistics Skill roll to fire? And if so, what (and where) are they?