the Bofors could put out a sustained 120 rounds per minute because of its constant-fire top-fed ammo clip design, whereas the 25mm's frequent ammo box changes lowered its nominal rate of fire to only half of its theoretical maximum of 260 rounds per minute). The Japanese ranked in order of seriousness the problems with the gun as: Elevation and traverse were too slow, even with powered mounts The sights were ineffective against high speed targets Firing the multiple mounts caused excessive vibration, which reduced accuracy and prevented effective target tracking Too little ammunition in each magazine resulted in a low overall rate of fire In Rapid Fire, Anthony Williams writes that the intermediate caliber weapons (including the US Navy's 1.1"/75 caliber gun 28×199mm L/75) were relatively unsuccessful during World War II: the mounts were much heavier and more complex than smaller calibre guns, but the shells lacked the range and hitting power of the larger 37 and 40 millimeter weapons. The Japanese viewed increasing the caliber of autocannons as the number one priority of research and development in the field. See also 25 mm automatic air defense gun M1940 (72-K) Bofors 25 mm M/32 25 mm variant of the Bofors 40 mm gun Notes References Bishop, Chris (eds) The Encyclopedia of Weapons of World War II. Barnes & Nobel. 1998. . Chant, Chris. Artillery of World War II, Zenith Press, 2001, . McLean, Donald B. Japanese Artillery; Weapons and Tactics. Wickenburg, Ariz.: Normount Technical Publications 1973. . External links Navweaps.com "Antiaircraft Artillery", TM-E 30-480: Handbook on Japanese Military Forces, U.S. War Department, October 1, 1944. 9 World War II anti-aircraft guns 9 World War II anti-tank guns World War II naval weapons Naval anti-aircraft guns Naval guns of Japan 25 mm artillery Military equipment introduced in the 1930s