Its failure to have much effect in the field led to a belief that rapid-fire weapons were useless. United States Army General William Babcock Hazen, who observed the war, commented that "The French mitrailleuse had failed to live up to expectations. The Germans hold it in great contempt, and it will hardly become a permanent military arm." Strictly speaking, manually operated volley guns such as the Reffye mitrailleuse were a technological dead-end, and they were soon replaced by fully automatic machine guns.