abstract:A personal defense weapon (PDW) is a compact semi-automatic or fully automatic firearm similar in most respects to a submachine gun, but firing a (often proprietary) rifle round, giving a PDW better range, accuracy and armor-penetrating capability than submachine guns, which fire pistol-caliber cartridges. The class of weapon as it exists today evolved as a hybrid between a submachine gun and a carbine, retaining the compact size and ammunition capacity of the former while adding the power, accuracy and penetration of the latter.