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Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons, particularly in larger calibres (12.7+mm).

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French Navy Model 1948 127mm/54   Naval Guns

Started 1-Nov by taschoene; 945 views.
taschoene

From: taschoene

1-Nov

Does anyone have and additional sources of information on this gun beyond what is available on the NavWeaps website (http://www.navweaps.com/Weapons/WNFR_5-54_m1948.php)

Superficially it seems like a good gun, firing US Navy standard ammunition at a reasonable rate of fire (~30 rpm total for both barrels, I think) and weighing considerably less than the US Mk42 for similar performance.  But it was withdrawn pretty quickly when the ships it was mounted on went in for guided missile conversions or modernization, usually replaced with 100mm guns.  So was it a bad gun or just replaced to free up weight for missiles and to standardize on the faster-firing 100mm?

Red7272

From: Red7272

1-Nov

It would have been manually loaded and needed turret, handling room and magazine crews.  Just saving on the 15/20 crew difference would have been worth the 12 tons difference. 

taschoene

From: taschoene

2-Nov

Red7272 said:

It would have been manually loaded and needed turret, handling room and magazine crews.  Just saving on the 15/20 crew difference would have been worth the 12 tons difference. 

Are you comparing to the Mk 42? I'm still trying to find out anything about the mechanism for the Model 1948.  There were several semi-automatic designs in this size range from about the same era (the Swedish 120mm twin and the abortive US Mk 41 twin, for example).  If the Model 1948 was also semi-automatic, it would probably have has a similar crew (anywhere from 12 to 20).  That's about the same as the early Mk 42.  If it was truly manual, then yes, it would have needed a lot more crew.  

Red7272

From: Red7272

2-Nov

taschoene said:

Are you comparing to the Mk 42?

You compared it to the Mk 42, and automatic guns don't have their rate of fire described as 15 to 18 rounds per minute. 

taschoene

From: taschoene

2-Nov

The target RoF for the Mk 41, a semi-automatic twin mount the USN was interested in late in WW2, was 18 rpm per tube (realistically, it probably would have fallen short of that). The Mk 42 is actually very similar to the Mk 41, just with two loading mechanism s feeding a single gun tube, and its realistic RoF is just under 30 rpm.  So yes, I think it is possible that the French Model 1948 was a semi-automatic twin mount with that RoF.  But I don't know for certain, because I haven't been able to find any information at all about how it operated.  

Red7272

From: Red7272

2-Nov

The mounting looks like the twin version of the pre war 13 cm DP.

The ROF is the same as the 13 cm DP mounting.

It's 1947, 3 years after the end of WWII.

It's a manual turret.

http://www.navweaps.com/Weapons/WNFR_51-45_m1932.php

TonyDiG

From: TonyDiG

3-Nov

"Jane's Pocket Book 9: Naval Armament" edited by Denis Archer (1976) gives the ROF as 15 rpm.

 

My speculation would be that the French were provided with technical help from the USN regarding the US 5"/54 Mark 16 (Midway class) as part of the contract for purchasing US ammunition.  Accordingly, the breech and loading arrangements would likely be very similar to the USN weapon.  Although it is identified as a "Model 1948" it was not actually in service until the mid-1950s vs. 1945 for the USN gun.  As such, it possibly has some improvements over the USN weapon.

 

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Edit

One thing that I should mention is that the ammunition feeds for the French gunhouses appear reversed from USN twin mounts.  The USN mountings had the shell and powder hoists on the inside of the guns.  So, the gun barrels are widely separated.  The barrel spacing on the French mountings are much closer together, which would lead me to say that the hoists were on the outside of the guns.  As such, there may have been shell interference unless there was a shot delay.

 

  • Edited 03 November 2020 8:54  by  TonyDiG
taschoene

From: taschoene

3-Nov

Thanks, Tony.  That seems plausible.  Just wish I could find some info on how well this mount actually worked.

taschoene

From: taschoene

3-Nov

TonyDiG said:

One thing that I should mention is that the ammunition feeds for the French gunhouses appear reversed from USN twin mounts.  The USN mountings had the shell and powder hoists on the inside of the guns.  So, the gun barrels are widely separated.  The barrel spacing on the French mountings are much closer together, which would lead me to say that the hoists were on the outside of the guns.  As such, there may have been shell interference unless there was a shot delay.

That suggests some similarity to the US Mk 41 -- it had tubes only 26 inches apart and fed from the outside toward the center.  Friedman has a cutaway drawing in Naval Anti-Aircraft Guns and Gunnery .

https://www.google.com/books/edition/Naval_Anti_Aircraft_Guns_and_Gunnery/rl8gDAAAQBAJ?hl=en&gbpv=1&pg=PA305&printsec=frontcover&bsq=41

TonyDiG

From: TonyDiG

3-Nov

taschoene said...

TonyDiG said:

One thing that I should mention is that the ammunition feeds for the French gunhouses appear reversed from USN twin mounts.  The USN mountings had the shell and powder hoists on the inside of the guns.  So, the gun barrels are widely separated.  The barrel spacing on the French mountings are much closer together, which would lead me to say that the hoists were on the outside of the guns.  As such, there may have been shell interference unless there was a shot delay.

 

That suggests some similarity to the US Mk 41 -- it had tubes only 26 inches apart and fed from the outside toward the center.  Friedman has a cutaway drawing in Naval Anti-Aircraft Guns and Gunnery .

https://www.google.com/books/edition/Naval_Anti_Aircraft_Guns_and_Gunnery/rl8gDAAAQBAJ?hl=en&gbpv=1&pg=PA305&printsec=frontcover&bsq=41

 

Correct.  That caught my eye as well.  One of the reasons why I thought of it when looking at the French twin mount.  It would not surprise me to learn that BuOrd shared both gun and mounting drawings with the French.  If you look at the 3"/70 Mark 37 twin mount, you'll see the same close barrel spacing.  Putting the hoists in-between the guns means a small below-decks footprint.  Putting them outside lets you squeeze machinery in the gunhouse corners out of the way of the gun crew.

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