TSWG = Technical Support Working Group. The Knight’s Armament Company 6×35mm PDW is an experimental personal defense weapon designed by Knight’s Armament Company (KAC), firing a 6mm cartridge optimized for short barrel weapons. As with all personal defense weapons, the KAC PDW is intended to be compact and lightweight (similar to submachine guns), but have a longer useful range (out to the low end of combat rifle ranges, 250–300 m). The KAC PDW fires a 6×35 mm cartridge, a full centimeter shorter than the western military standard 5.56×45mm NATO round. The 6mm bullet is slightly wider, and the standard 6×35mm bullet slightly heavier, than the standard 5.56mm bullet (65 grains (4.2 g) versus 62 grains (4.0 g)). Fired from a 10-inch (250 mm) barrel, KAC claims that the 6×35mm cartridge reaches a muzzle velocity of 2,450 ft/s (750 m/s), slightly faster than the muzzle velocity of a 5.56 mm cartridge fired from a similarly short barrel. The larger diameter, shorter 6 mm cartridge is optimized for these shorter barrel lengths, and would perform less efficiently from rifle-length barrels. The round’s muzzle energy is 831 ft·lbf (1,127 J) versus 792 ft·lbf (1,074 J) for a 5.56 mm bullet, again from the same 10″ standard barrel.