The rail-mounted weapon could hurl a 120 kg shell with 7 kg of explosive to a range of 131 km. During the 170 second trajectory the shell reached a maximum altitude at the edge of space - 40 km. This was the highest altitude attained by a man-made object until the first successful V-2 flight. From March through August of 1918, three of the guns shot 351 shells at Paris from the woods of Crepy, killing 256 and wounding 620. As a military weapon the gun was a failure - the payload was minuscule, the barrel needed replacement after 65 shots, and the accuracy was only good enough for city-sized targets. But as a psychological tool it was remembered when the V-1, V-2 and V-3 weapons were being developed two decades later.

After demonstrations to Army officers of work achieved at Mt Wilson, Goddard is requested to demonstrate his rockets at the Aberdeen Proving Ground in Maryland. The scientists and representatives of the Signal Corps, Air Service, Army Ordnance, are most impressed ('this will revolutionise warfare'). Goddard admits that his cartridge rocket concepts have been less successful and 'need further work'. The next day, Germany surrenders, World War I ends, and funding dries up.