The Heckler & Koch HK53A3 is a germany-made select-fire carbine chambered in 5.56x45mm NATO, introduced in 1975. Primary use: military. Type: Carbine Action: Select-Fire Caliber: 5.56x45mm NATO Capacity: 30 Year introduced: 1975, Germany Weight: 160 oz Overall length: 38.5" Status: Discontinued Intended use: military