The main armament was the 380 mm "Raketen-Werfer" 61 L/5.4, a breech-loading barrel, which fired a short-range, rocket-propelled projectile roughly long. There were a variety of round types with a weight of up to , and a maximum range of up to , which either contained a high explosive charge of or a shaped charge for use against fortifications, which could penetrate up to of reinforced concrete. The stated range of the former was . A normal charge first accelerated the projectile to , the rocket charge then boosted this to about .