WesWorld

The current sem-auto 57mm is a developement by Madsen in collaberation with Iberian Arms Industries, of the earlier Iberian 57mm breech loader, using Madsen's 37mm semi-auto as a starting point. (Check out the older news threads, it was a little over a year in developement)

Demmark's new coastal patrol boats will be carrying it, basically as a weight saving compromise over a larger calibre, but still has enough punch to deal with any smuggler, or God forbid, torpedo boat or sub on the surface.

57mm guns are historical and roughly normally equate to the old 6pdr QF guns of the 1890s and others like the 57mm Nordenfelt. I guess as an 'odd' calibre it died a death until the post war period.

Semi-auto 57mms, like the 6pdr 7 and 10 cwt guns used by the RN during the war, are fine, whether they're manually loaded like the 10cwt or mechanically loaded like the 7cwt with the Mollins loading gear. It's automatic 57mms that are problematic, there weren't any that were fielded before the 1950s.

Exactly.


Of course, the Italian 65mm suffered from similar problems, eventually reverting to hand loading and a rate of fire of around 20 rpm. About the only "Intermediate AA gun" that worked mechanically during the period was the 50mm Flak 41, and it was so crippled by a bad mount (unstable in transit, too tall, and too slow in traverse) and bad sights (inadequate prediction, inaccurate) that only 200 or less were built. Further development probably could have fixed some or all of the mount problems and the inaccuracy of the sights (without radar, prediction would likely remain a problem), but instead a great leap forwards was attempted with the 55mm Gerat 58. The 55mm Gerat 58 MIGHT have worked, but only 2 prototypes were built by the end of the war so it's hard to know for sure (I've seen some claims that it was further developed into the post-war Russian 57mm AA guns like the S-60).

Quoted

Of course, the Italian 65mm suffered from similar problems, eventually reverting to hand loading and a rate of fire of around 20 rpm.

The 65/64 reverted to automatic loading postwar and served as the test piece for OTO's new 76/62 automatic. The change in calibre seems to have been to include proximity fuses and improve commonality with the rest of NATO. They aimed for a fair bit less than the 55mm G58 at around 60-70rpm sustained. The UK did a lot with automatic weapons in the immediate postwar period gettting up to 80-90rpm for various 3.7" and 4" weapons but these aren't sustained rates.

Quoted

Originally posted by Red Admiral

Quoted

Of course, the Italian 65mm suffered from similar problems, eventually reverting to hand loading and a rate of fire of around 20 rpm.

The 65/64 reverted to automatic loading postwar and served as the test piece for OTO's new 76/62 automatic. The change in calibre seems to have been to include proximity fuses and improve commonality with the rest of NATO. They aimed for a fair bit less than the 55mm G58 at around 60-70rpm sustained. The UK did a lot with automatic weapons in the immediate postwar period gettting up to 80-90rpm for various 3.7" and 4" weapons but these aren't sustained rates.

The Italian 76mm/62 didn't enter service until the early 1960s.

Agreed, the G58 was EXTREMELY ambitious, I've doubts about how easily it could be fed aboard ship with a clip-weight of over 60 pounds per 5 round clip (even if you remove the issues with the on-mount radar that it was intended to have).

Quoted

The Italian 76mm/62 didn't enter service until the early 1960s.

First use was when the Albatros class corvettes completed in 1955, which happened to be the first ships built since 1943.... then the duple mount appeared in 1959 on Centauro but that didn't work very well.

Quoted

Originally posted by Hrolf Hakonson
About the only "Intermediate AA gun" that worked mechanically during the period was the 50mm Flak 41, and it was so crippled by a bad mount (unstable in transit, too tall, and too slow in traverse) and bad sights (inadequate prediction, inaccurate) that only 200 or less were built.

You mention inaccuracy and attribute it to sights, my little Hogg book claims it 'vibrated badly when firing' and attributes the inaccuracy to that. It does say the sight was to complicated and a source of further errors. Don't know if Hogg is correct, but that would be a reasonable problem for higher ROF autocannons.

As for the 76/62, the USN 3" came out in 1946 with a ROF of 45-50 rounds, and was indeed chosen around the smallest VT round.

There's a video here of the Molins 57mm gun with an autoloader on a wheeled carriage. It can be seen that there's quite some recoil there.

They put THAT thing in an aircraft!

It forces me to consider blast and recoil on my 6pdr AA gun.

Quoted

Originally posted by Kaiser Kirk

Quoted

Originally posted by Hrolf Hakonson
About the only "Intermediate AA gun" that worked mechanically during the period was the 50mm Flak 41, and it was so crippled by a bad mount (unstable in transit, too tall, and too slow in traverse) and bad sights (inadequate prediction, inaccurate) that only 200 or less were built.

You mention inaccuracy and attribute it to sights, my little Hogg book claims it 'vibrated badly when firing' and attributes the inaccuracy to that. It does say the sight was to complicated and a source of further errors. Don't know if Hogg is correct, but that would be a reasonable problem for higher ROF autocannons

If vibration was a problem that caused the inaccuracy, then I can see it having two causes: either the mount was faulty (which it was in various ways already noted), or the sight mounting was, causing it to move and not "hold zero". Either way, it's a problem that could have been fixed, but the work historically wasn't done.

I came up with te idea of sticking with 57 mm when I invented Iberia. 76mm autos were used in the USN just after the war. So I figured "what if". 57mm should be easier than 76 mm. It is a lot closer to 40mm which was common in the war.