For the best medium AA mounting on a warship my vote goes for the 40mm bofors. A Swedish design, used by the US, British, German, and Japanese navies, (and versions used by these countries ground forces). It was reliable, had a heavy weight shell, a high rate of fire (120 rds per minute, per barrel) and when powered and tied to the Mk 51 director was extremely effective. 40mm US quad mounting. Mk 51 director. Any other contestants?
40mm is "medium" ? curently medium are in the 57 to 76mm range, they were able to fire proximity fused ammo long before miniaturization tech made it possible for the 40mm. IMO it carries the field because of the very poor contestants. AFAIK they were - The horrible fixed recoil Italian 37mm breda - The German 37/L83 SK/30 that loaded rounds individually - The Britisk 40mm pom pom with it's poor initial velocity - The Soviet 37/57 was very "Bofors inspired" - The Soviet 45/68 also loaded rounds individually but was a step in the right direction (something big enough to fire PX) The German navy use was limited, I believe they used some guns produced in Norway but never built them in German factories despite the close ties between Bofors and Krupp. Do you have references to Japanese usage? AFAIK they badly needed something better than their lackluster 25mm but never got anything in large scale production. IMO no history of the Bofors 40/56 would be complete without the Dutch/British advanced mounts (Hazemeyer and derivatives), possibly too advanced for 1940 tech but a forerunner of contemporary integrated mounts.
Love the photo. The mount is obviously under director control, no one is sitting in either seat. Kinda wondering what ship, with the open mount 5" in the background.
Propably is the 40mm Bofors the best, but the german 3,cm C30 wasn´t that bad too! View attachment 13597
Yes, the Germans had a good combination with the later 37mm and 20mm. Often overlooked, the Italians had their own 37mm and 20mm Breda guns, both of which were quite capable.
In the US Navy the 40mm bofors was replaced by the rapid fire 3"/50 Mk 33 (76.2mm) mount post WWII because the 40mm bofors lacked the power to adequately deal with newer, heavier and faster aircraft. 3"/50 Mk 33 mount circa 1954. Thanks for naming some more contestants, even if you think them inferior. Good data, and moves the discussion along. You are correct sir, the guns were produced in Norway. They were designated the 4 cm/56 Flak 28. There is a picture of one mounted on the Prince Eugen at this site (along with quite a few other mountings). Sweden, British, USA, German and Japanese Bofors 40 mm/56 (1.57") Model 1936 Pictures They were a knock off of a captured British Army air-cooled version (US twin and quad mounts were water-cooled) captured in Singapore and were designated the 4 cm/60 Type 5. They modified the design but poor production quality led to them being unreliable. Only small numbers were produced but they were used on a limited basis. The gun is mentioned in a postwar U.S. Naval Technical Report, O-47(N)-2.
The Bofors had an effective "slant" range of 4 miles. Why wouldn't they just give a vertical height?... The German 37mm Flak 36 AA gun looked good. Looks similar to the Bofors. Smaller, top feed.
One "feature" of the 37mm Breda twin mouns was the lack of a recoil mechanism that made the mount unsuitable for anything smaller than a cruiser as sustained fire would damage the lighter plates of smaller vessels, it existed in both water (older) and air cooled versions. The single mounts installed forward of the main guns in the battleships did have a recoil absorber as the "collapsible mount" (the gun retreated in a well when the main guns fired) was too light to absorb the recoil energy, it was finally developed into a mount that could be installed in destroyer sized ships, typical Italian weapon mix of over and under engineering in the same weapon. The 20/65 mm Breda also lacked a recoil system but with it's less powerful round it was less of a problem, the Scotti 20/70 was similar and after 1941 the Regia Marina also used a number of Oerlikons 20/70 (IMO the real "universal gun" of WW2). The Regia Marina also still had some Vickers 40/39 of WW1 vintage in service in 1940.
Very good info TOS, thanks. I also agree with you on the 20mm Oerlikon being the real "universal gun" but it would be under the heading of light AA gun and I didn't start a thread for "best light AA mount" because the Oerlikon, IMO, would be the only contender.
