The jeep being too light to mount substantial guns, it was more suited later in the war, as a platform for rocket artillery, that didn't have the enormous recoil as conventional tube artillery. The California Institute of Technology developed two different 4.5in jeep-based rocket launcher systems for the U.S. Navy. Several other initiatives all used 4.5in rockets and tubes. Testing was also done by both U.S. Army and Marine Corps, but none of the jeep-mounted rocket launchers were built in any significant number, because it was more efficient to use larger trucks that could carry more rockets. The Soviet Red Army deployed twelve units fitted with 12-rail M8, 82mm rocket launchers in the bed of a jeep, from December 1944 in the Carpathian Mountains.