Austrian Steyr Mannlicher and German Rheinmetall Defence companies partnered to offer another contender for the German Armed Forces’ pursuit of new assault rifle to replace its Heckler and Koch G36s. The RS556’s design is based on Steyr's STM556 rifle however with some enhancements. Reportedly, RS556 has a variety of barrel length options, enabling the weapon to be configured as a storm gun, a machine gun or a light machine gun, and its barrel can be replaced without any tools within seconds. Thanks to its anti-corrosive Mannox coating, the rifle also works without gun oil.