France
138.6 mm/45 (5.46") Models 1929 and 1934
Updated 28 March 2012
The success of the 138.6 mm/40 (5.46") Model 1927 led to the development of these more powerful weapons.  For the first time, power elevation and training were provided to destroyer gun mounts, which arguably made them France's best destroyer guns of World War II.  Unfortunately, the lack of a high elevation capability made them useless against aircraft.  They were also fragile and complicated weapons, conditions which made it difficult for them to achieve their official rate of fire.  Problems with the ammunition hoists were reportedly corrected in March 1940.

The main difference between Model 1929 and Model 1934 was the mounting arrangements.  The Model 1929 was designed for single mountings while the Model 1934 was designed for twin mountings.  The twin mounting was also weather enclosed, which offered obvious operational advantages over the open mountings used on all previous French destroyers.

Built with a monobloc autofretted barrel and a breech ring that was screwed on cold.  The breech mechanism was a sliding block of semi-automatic operation.
WNFR_55-45_m1929_LeTriomphant_pic.jpg

Model 1929 Single Mountings on Le Triomphant in 1940
Note the twin 13.2 mm MG on the bridge
WNFR_55-45_m1929_Mogador.jpg

Model 1934 Mountings on Mogador at Le Harve on 12 November 1938
Note the very poor sky arc of the twin 13.2 mm MG alongside the bridge
Photograph copyright by Robert Dumas
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Gun Characteristics
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Designation 138.6 mm/45 (5.46") Model 1929 and 1934
Ship Class Used On Model 1929:  Le Fantasque (2,610 tonnes) class

Model 1934:  Volta (2,930 tonnes) class.  Planned for the Kléber and Bruix classes
Date Of Design 1929 / 1934
Date In Service 1935 / 1939
Gun Weight Model 1929:  4.21 tons (4.28 mt)
Model 1934:  4.58 tons (4.65 mt)
Gun Length oa 286.6 in (7.280 m)
Bore Length 272.7 in (6.927 m)
Rifling Length 229.7 in (5.836 m)
Grooves (42) 0.048 in deep x 0.289 (?) (1.22 mm x 7.35 mm (?))
Lands 0.118 (3 mm) (?)
Twist Uniform RH 1 in 22.35
Chamber Volume 1,242 in3 (20.36 dm3)
Rate Of Fire
(see Note)		 Model 1929:  12 rounds per minute maximum, 7 rounds per minute practical

Model 1934:  6 to 7.5 rounds per minute
Note:  The Model 1934 used a catapult rammer for projectiles, but ammunition handling arrangements were complex and prone to breakdown.  Early trials for this model showed a rate of fire of 3 to 4 rounds per minute with jams and frequent failures.
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Ammunition
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Type Separate
Projectile Types and Weights OPF Model 1924 (SAP) - 89.5 lbs. (40.6 kg)
OEA Model 1932 (HE) - 89.5 lbs. (40.6 kg)
Bursting Charge SAP - 5.3 lbs. (2.4 kg)
HE - 9.0 lbs. (4.1 kg)
Projectile Length SAP - 26.9 in (68.3 cm)
HE - 27.3 in (69.3 cm)
Cartridge Case Type, Size and Empty Weight Brass, 130 x 900 mm, 28.57 lbs. (12.96 kg)
Cartridge lip was 7.38 in (18.75 cm)
Propellant Charge 26.65 lbs. (12.09 kg) BM11
Cartridge weight filled - 52.07 lbs. (23.62 kg)
Muzzle Velocity SAP:  2,625 fps (800 mps)
HE:  2,756 fps (840 mps)
Working Pressure 15.9 tons/in2 (2,500 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun
(see Note 1)		 Le Fantasque:  240 rounds
Volta:  180 rounds
Notes:

1) Wartime outfit for the Volta class was 1,440 rounds of HE and SAP plus 85 starshells.  Peacetime outfit was 650 rounds of HE and SAP plus 75 starshells.  There was room to store 1,590 cartridge cases and starshell was stored in a separate ammunition room which fed turret number 2.  Following initial trials, ready-use racks holding five complete rounds were worked into each turret in order to compensate for the frequent breakdowns in the ammunition supply systems.

2) The same size cartridge case was used in all 138.6 mm (5.46") guns from the Model 1910 onwards, although the type and quantity of propellant was not always the same.  This allowed obvious advantages in terms of standardization, although much of this was lost by the fact that almost every model used different projectiles.

3) In the spring of 1940 dye-filled OPFK (SAP) shells were issued.  It was customary that the first ship in a division used green dye, the second white - later yellow - and the third red.
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Range
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Elevation With 89.5 lbs. (40.6 kg) SAP Shell
Range @ 30 degrees 21,872 yards (20,000 m)
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Mount / Turret Data
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Designation Single Open Mounts
   Le Fantasque (5):  Model 1929

Two-gun Enclosed Mounts
   Volta (3):  Model 1934
   Kléber (4):  Model 1938 (?)
Weight  Model 1929:  11.39 tons (11.57 mt)

Model 1934:  34.05 tons (34.6 mt)
Elevation Model 1929 and 1934:  -10 / +30 degrees
Model 1938:  -10 (?) / +35 degrees
Elevation Rate Model 1929:  Manually operated, only

Model 1934:  14 degrees per second
Train about +150 / -150 degrees
Train Rate Model 1929:  Manually operated, only

Model 1934:  10 degrees per second
Gun recoil 20 in (50 cm)
Loading Angle Any (see Note 3)
Notes: 

1) Later ships of the Kléber class would have had a maximum elevation of +35 degrees, but these ships were cancelled upon France's defeat in 1940.

2) Single mounts were manually trained and elevated.  There were four shell and four cartridge dredger hoists in the fixed structure, with guns Numbers 3 and 4 sharing one set.  Ammunition slides ran from the hoists to the guns.  These guns had automatic spring-powered rammers.

3) The following description is adapted from "Naval Weapons of World War Two" regarding Model 1934 mountings:

Two-gun mounts [Model 1934]  were essentially "base-ring" semi-turrets with the guns in separate sleeves which could be coupled together.  Training and elevation were powered by 3 hp Leonard electric motors with RPC.  Each gun had a pusher shell and cartridge hoists in a fixed shaft on the mounting axis.  Ammunition was transferred to a rotatable tipping drum from which it slid out into the loading mechanism.  A catapult rammer was used for shells, but the cartridges were manually rammed.  Loading was at any elevation, but the mechanism was prone to defects and jams and the intended rate of fire was not achieved.  The distance between the gun axes was 52.4 in (133 cm).
In addition, John Jordan in "The Contre-Torpilleurs of the Mogador Class" says that the catapult rammers were so underpowered that loading was impossible at any angle above +10 degrees.  The elevation and training motors were originally inside the mountings, but were moved to external "pods" in order to free up space for ready ammunition racks.

4) No. 4 gun was removed from Le Triomphant during a 1940 refit in Britain and a 4"/45 (10.2 cm) for AA use was fitted in its place.  British light AA guns were also fitted in place of the original French AA guns at this time.

5) Gun crews for each two-gun turret were eight crewmen plus a commander for each pair of turrets.  Only two of these were loaders and maintaining a high rate of fire was physically intensive, leading to a diminishing rate of fire during prolonged firing periods.
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Data from
"Naval Weapons of World War Two" by John Campbell
"The Last Super Destroyers?:  Mogador and Kleber Classes" article by Robert Dumas in "Warship Volume VIII"
"The Contre-Torpilleurs of the Mogador Class" by John Jordan article in "Warship 2007"
"Navies of the Second World War - The French Navy" by Henri le Masson
"The French Fantasque Class, 1930" article by Jacques Mordal in "Warship Special 2:  Super Destroyers" edited by Antony Preston
"Destroyers of World War Two" by M.J. Whitley
Page History

14 October 2007 - Benchmark
31 March 2010 - Corrected typographical error
28 March 2012 - Updated to latest template