French
330 mm/50 (13") Model 1931
Updated 23 May 2006
These guns were used to arm the first French capital ships built since World War I, the Dunkerque class.  These weapons had a high muzzle velocity, which gave them long range and good vertical armor penetration at the cost of having poor deck penetration.  They were mounted in quad turrets, which were really more of a dual-twin arrangement.  The design of the turret was taken from the Normandie class.

Although equipped with RPC, the Sautter-Harlé-Blondel gear for these turrets was apparently far from satisfactory.  As the guns were closely spaced together, these ships also suffered from problems with excessive dispersion.

The dual quad-gun turret arrangement was calculated to be 27.6% lighter than a quad twin-gun arrangement, but it did mean that a single hit could eliminate half of the main battery.

The construction of these weapons is not clear, but it is believed to have been similar to that of the 380 mm/45 (14.96") guns used on the Richelieu.  Actual bore length was 50.44 calibers.

Some of the APC shells for these guns were converted to aircraft AP bombs.

A note on sources:  "Battleships:  Allied Battleships in World War II" and "Battleships of the World 1905-1970" list this weapon as "330 mm/52" but, as noted above, the actual bore length was 50.44 calibers.
WNFR_13-50_m1931_Dunkerque_pic.jpg

Dunkerque in 1939
Photograph courtesy of Charles Cordier
WNFR_13-50_m1931_Strasbourg_pic.jpg

Strasbourg in 1938
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Gun Characteristics
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Designation 330 mm/50 (13") Model 1931
Ship Class Used On Dunkerque Class
Date Of Design 1931
Date In Service 1939
Gun Weight 155,503 lbs (70,535 kg)
Gun Length oa 676.0 in (17.170 m)
Bore Length 655.3 in (16.645 m)
Rifling Length 548.8 in (13.940 m)
Grooves (80) 0.126 in deep x 0.304 in (?) (3.2 mm x 7.73 mm)
Lands 0.205 in (?) (5.2 mm)
Twist Uniform RH 1 in 25.57
Chamber Volume 17,880 in3 (293 dm3)
Rate Of Fire 1.5 - 2 rounds per minute
Note:  The intended rate of fire was 3 rounds per minute.  However, the shell supply arrangements in the shell rooms proved to be inadequate and the designed ROF was never met.
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Ammunition
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Type Bag
Projectile Types and Weights APC - 1,235 lbs. (560 kg)
HE - 1,151 lbs. (552 kg)
Bursting Charge APC - 44.7 lbs. (20.3 kg)
HE - 140 lbs. (63.5 kg)
Projectile Length about 65 in (165 cm)
Propellant Charge 423 lbs. (192 kg) SD19
Muzzle Velocity APC - 2,854 fps (870 mps)
HE - 2,904 fps (885 mps)
Working Pressure 20.3 tons/in2 (3,200 kg/cm2)
Approximate Barrel Life 250 rounds
Ammunition stowage per gun about 100 rounds
Notes:

1) Propellant charges were in quarters.

2) Aircraft AP bomb weighed 1,235 lbs. (560 kg) and was designated as M1939.
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Range
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Elevation
With 1,235 lbs. (560 kg) APC
Striking Velocity
Angle of Fall
4.3 degrees
10,936 yards (10,000 m)
2,261 fps (689 mps)
5.2
7.2 degrees
16,404 yards (15,000 m)
2,005 fps (611 mps)
9.1
10.2 degrees
21,872 yards (20,000 m)
1,755 fps (535 mps)
14.2
14.8 degrees
27,340 yards (25,000 m)
1,614 fps (492 mps)
21.3
19.6 degrees
32,808 yards (30,000 m)
1,529 fps (466 mps)
28.8
25.4 degrees
38,276 yards (35,000 m)
1,512 fps (461 mps)
36.8
35.0 degrees
45,604 yards (41,700 m)
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---
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Elevation
With 1,151 lbs. (522 kg) HE Shell
35.0 degrees
44,401 yards (40,600 m)
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Armor Penetration with 1,235 lbs. (560 kg) APC Shell
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Range
Side Armor
Deck Armor
0 yards (0 m)
28.08" (713 mm)
--
25,153 yards (23,000 m)
13.46" (342 mm)
3.47" (105 mm)
30,114 yards (27,500 m)
11.48" (292 mm)
4.32" (110 mm)
Note:  This data is from "Battleships:  Allied Battleships in World War II" for a muzzle velocity of 2,854 fps (870 mps) and is based upon the USN Empirical Formula for Armor Penetration.
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Mount / Turret Data
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Designation Quad Mount
   Dunkerque (2):  Model 1931
Weight 1,473 tons (1,497 mt)
Elevation -5 / +35 degrees
Rate of Elevation 6 degrees per second
Train Turret I:  +/- 143 degrees 
Turret II:  +/- 150 degrees
Rate of Train 5 degrees per second
Gun Recoil 45.3 in (1.15 m)
Loading Angle Any angle
Notes:

1) These guns were sleeved in pairs.  There was apparently some adjustment between the guns in a pair, possibly for alignment purposes.

2) These mountings were developed by St Chamond and were electrically powered.  The supporting ball race contained 152 balls of 7.17 in (18.2 cm) diameter.

3) The gunhouse was divided internally by a 4 cm (1.6") bulkhead.

4) Heavy leather blast bags were fitted to the main gun embrasures in 1939.

5) Two 100 hp training motors were in each mounting, either one of which could be used to train the turret.  There were two elevation motors, each rated for 75 hp.

6) The gun axis in each pair were 66.5 in (169 cm) apart while the two inner guns were 100 in (254 cm) apart.
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Data from
"Battleships of the World 1905-1970" by Siegfried Breyer
"Naval Weapons of World War Two" by John Campbell
"Battleships:  Allied Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"The Big Gun:  Battleship Main Armament 1860-1945" by Peter Hodges
"Battleships of World War Two" by M.J. Whitley