USN Interwar gun designs

[Tzoli]

Norman Friedman mentions 2 guns for the USN in a number of his books in the 1920-30 timeframe.

First is a 37mm Machine Cannon intended as a primary light AA gun for the 1920's warship designs (Heavy Cruisers and Battleships) I don't know if any development was done or was it used for developing other weapons (1,1" or the 37mm M1? )

The second is the 5,3" DP-gun which was developed into the famous 5"/38 Mark 12 gun, the 1928/29 Battleship studies shows this as their primary DP-AA weapon in twin mountings. But I could not find any other mention of them.

Does anybody know anything about these?

 

[TomS]

First is a 37mm Machine Cannon intended as a primary light AA gun for the 1920's warship designs (Heavy Cruisers and Battleships) I don't know if any development was done or was it used for developing other weapons (1,1" or the 37mm M1? )

Friedman goes into a little more detail in Naval Anti-Aircraft Guns and Gunnery. He says there was an October 1928 request from Admiral Leahy of BuOrd to look at the Army/Colt 37mm cannon (which I think eventually became the M1). BuOrd liked it for the 1-lb shell, which had a nominal velocity of 2800 fps. (The finished M1 for the Army has a heavier HE shell and lower velocity) The Navy asked for two test examples, with right and left-hand clip feed, with the goal to design a six-gun mount. But the Navy's ultimate desire was to design a 25mm version with longer shells of similar weight but better ballistics, possibly belt fed. It looks like Colt was unwilling to commit the engineering for that and it eventually came to nothing. Then the Navy went forward with its own 1.1-inch design and the rest, as they say, is history. (In 1930, the Navy also designed its own 37mm round and started work on its own 37mm gun, but abandoned it pretty quickly.)

(Oddly, in 1936 the Navy apparently received an offer from Rheinmetall for single and twin 3.7cm automatic guns, as well as Soluthern 2cm guns.)

The second is the 5,3" DP-gun which was developed into the famous 5"/38 Mark 12 gun,

Friedman mentions a 5.4"/40 design from BuOrd in this timeframe. This had a 75-lb shell with a separate case. It had a manually loaded ROF of 12 rpm on large ships (much less on small ones, probably). This was a bit too heavy to maintain the RoF, especially at high angles, so they went down to 5"/40 with a 54-lb shell weight. During development, they cut the barrel down a couple of calibers and we got the iconic 5"/38. There is some more info in the footnotes regarding mount weight and so forth that I'm too lazy to transcribe right now.

 

[Scott Kenny]

Friedman goes into a little more detail in Naval Anti-Aircraft Guns and Gunnery. He says there was an October 1928 request from Admiral Leahy of BuOrd to look at the Army/Colt 37mm cannon (which I think eventually became the M1). BuOrd liked it for the 1-lb shell, which had a nominal velocity of 2800 fps. (The finished M1 for the Army has a heavier HE shell and lower velocity) The Navy asked for two test examples, with right and left-hand clip feed, with the goal to design a six-gun mount. But the Navy's ultimate desire was to design a 25mm version with longer shells of similar weight but better ballistics, possibly belt fed. It looks like Colt was unwilling to commit the engineering for that and it eventually came to nothing. Then the Navy went forward with its own 1.1-inch design and the rest, as they say, is history. (In 1930, the Navy also designed its own 37mm round and started work on its own 37mm gun, but abandoned it pretty quickly.)

Too bad the 1.1" ended up being a total dog.

 

[Tzoli]

Thank you! Any other info on the 5,3/5,4" gun? Muzzle Velocity, turret shape?

 

[TomS]

Thank you! Any other info on the 5,3/5,4" gun? Muzzle Velocity, turret shape?

It would have been a twin mount but there are no sketches. It would have been powered in train and elevation, as well as loading (but still requiring manhandling from hoist to feed tray). The intent was for new battleships to have 18 5.4"/40 guns (9 twin mounts) in place of 8 5"/25 and 12 5"/51 in older ships.

Velocity was 2,600 ft/sec with a range of 20,000 yards and a ceiling of 40,000 feet.

 

[Tzoli]

Actually 8 twin mounts were envisioned for the 1928 series of battleship designs. But reading Friedman's description on these is quite difficult....

Is there an MV value for the 5"/40 direct predecessor of the/38 gun?
Any designation mentions? Say Mark A or Mark F etc?

 

[TomS]

Actually 8 twin mounts were envisioned for the 1928 series of battleship designs. But reading Friedman's description on these is quite difficult....

Quite possibly this is the difference between BuOrd's idea based on the weights of the various mounts and BuShips' ideas of what they could actually arrange on the ship. That ninth twin mount would have to be on centerline, which was in short supply on those designs, IIRC.

Is there an MV value for the 5"/40 direct predecessor of the/38 gun?
Any designation mentions? Say Mark A or Mark F etc?

Nothing on designation, and the velocity was the same, at 2,600 ft/sec from a new gun. Probably that's why the barrel got shorter--they realized that the 40-caliber tube was excessive for the chosen powder charge and they could use a 38-caliber tube for the same performance.

 

[Tzoli]

Interesting!
Thanks, in the end the 5"/38 Mark 12 mostly fired 55,18lbs (25kg) or 54lbs (24,5kg) shells at 2600ft/s (792m/s)

 

[TomS]

Interesting!
Thanks, in the end the 5"/38 Mark 12 mostly fired 55,18lbs (25kg) or 54lbs (24,5kg) shells at 2600ft/s (792m/s)

Yep, the 5"/38 and 5"/40 had the same ammo and charge. That 2-caliber barrel reduction was almost cosmetic, though I expect losing 10 inches off the working circle was helpful to BuShips.