Sub Machine Gun
A submachine gun (SMG) is a type of firearm that combines automatic fire with pistol-sized rounds, and is usually between the two in terms of weight. The submachine gun was first developed during the late stages of World War 1 as a way to improve trench warfare, but the war ended before major improvements could be made. These improvements took place during the years leading up to World War 2, during which practically every country involved in the war had at least one type of SMG, and new developments continue to be made to this day.
SMGs are short-range weapons, resulting from both their low-powered rounds (when compared to those of assault rifles and full-sized machine guns) and short barrels. The small rounds allow for larger magazine capacity, though while some SMGs like the M1928 Thompson "Tommy Gun" and the Russian PPSh-41 use drum magazines carrying 50 rounds or more, the average SMG magazine holds 20-30 rounds. The SMG's high rate of fire contribute to their effectiveness in close quarters battle, though some submachine guns like the MAC-10 or Micro Uzi (which fall under the sub-class of machine pistols) have such a high rate of fire that it causes the weapon's accuracy to suffer.
Most SMGs are meant to be fired from the shoulder, and thus are built with a stock, though in many cases the stock is collapsible. This doesn't prevent users from firing from the hip or other unorthodox position, however, thanks to the weapon's size and weight.
Varieties of SMGs in Grand Theft Auto:
Uzi Carbine
MP5 and variants
Skorpion vz.61