Two-handed SMGs and, partially, Carbines fall under this category. These weapons have higher volume of fire and easier operation than Rifles, as well as faster aiming, usually allowing them to fire two aimed shots per turn. They often have reduced single-handed use penalty (per gun description), and can be fired in melee at 90-100% accuracy. Also they're usually capable of Spray fire. Thus they're particularly good at delivering high amounts of pain at medium ranges.