French
340 mm/45 (13.4") Model 1912
Updated 12 August 2006
The building of Britain's "Super-Dreadnoughts" prompted France to increase the size of her battleship guns as well.  This meant a reduction from twelve main guns to ten, but this was more than offset by the abandonment of wing turrets in favor of having all turrets on the centerline.

These guns were considered to be an excellent weapon by the French, but the ships they were installed on were handicapped by poor fire control and low maximum turret elevations.  Salvo dispersions at their maximum range of 15,860 yards (14,500 m) was 330 feet (100 m).

Some of the unused guns intended for the never built Normandie class were used to rearm the Bretagne class when they were reconstructed in the 1930s.  Other spare guns were later used as coast artillery, with four guns in two twin turrets mounted at Cap Cepet near Toulon and four amore guns mounted in a French version of the German BSG mounting and used at Plouharnel near Quiberon.  Additional spare guns were used on railway mountings.

The construction was generally similar to that of the 380 mm (14.96") guns used on the later Richelieu class battleships, but there was an additional C tube and no loose liner.  The Welin breech block is believed to have opened horizontally.  Actual bore length was 45.82 calibers.
WNFR_134-45_m1912_Provence_pic.jpg

NMN Provence
Note missing casemate guns
WNFR_134-45_m1912_Bretagne_pic.jpg

NMN Bretagne about 1918
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Gun Characteristics
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Designation 340 mm/45 (13.4") Model 1912
Ship Class Used On Bretagne, Normandie and Lille classes
Date Of Design 1912
Date In Service 1915
Gun Weight 65.89 tons (66.95 mt)
Gun Length oa 634.5 in (16.115 m)
Bore Length 613.4 in (15.580 m)
Rifling Length 521.7 in (13.250 m)
Grooves (102) 0.075 in deep x 0.295 in (1.9 mm x 7.5 mm)
Lands 0.118 in (3.0 mm)
Twist Uniform RH 1 in 29.89
Chamber Volume 15,646 in3 (256.4 dm3)
Rate Of Fire about 2 rounds per minute
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Ammunition
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Type Bag
Projectile Types and Weights APC M1912 - 1,224 lbs. (555 kg)
APC M1924 - 1,268 lbs. (575 kg)
HE M1926 - 842 lbs. (382 kg)
HE 15A - 1,025 lbs. (465 kg)
HE17 FATO - 981 lbs. (445 kg)
HE FATO 32-6 - 952 lbs. (431.8 kg)
Bursting Charge APC M1924 - 47.8 lbs. (21.7 kg)
Others - N/A
Projectile Length APC M1912 - 49.5 in (125.8 cm)
APC M1924 - 58.9 in (149.6 cm)
HE M1926 - 41.5 in (105.4 cm)
Others - N/A
Propellant Charge APC M1912 - 338.4 lbs. (153.5 kg) BM 16
APC M1924 - 338.4 lbs. (153.5 kg) BM 16
HE M1926 - 308.6 lbs. (140 kg) BM 15
HE 15A - 338.4 lbs. (153.5 kg) BM 16
HE 17 FATO - 390 lbs. (177 kg) SD19G
HE FATO 32-6 - 390 lbs. (177 kg) SD19G
Muzzle Velocity APC M1912 - 2,605 fps (794 mps)
APC M1924 - 2,559 fps (780 mps)
HE M1926 - 2,904 fps (885 mps)
HE 15A - 2,930 fps (893 mps)
HE 17 FATO - 3,005 fps (916 mps)
HE FATO 32-6 - 3,022 fps (921 mps)
Working Pressure 17.8 tons/in2 (2,800 kg/cm2)
Approximate Barrel Life about 250 rounds
Ammunition stowage per gun Bretagne:  100 rounds
Others:  N/A, but probably 100 rounds
Notes:

1) Propellant was in four bags.

2) Of the shells listed above, only the first three were used on ships, the others were for Railway guns.

3) It is not known how many ships were modified to carry the significantly longer APC M1924.

4) The APC M1912 was modified to add dye bags around 1940 (K version).  These weighed 1,230 lbs. (558 kg) and were 50.9 inches (129.2 cm) long.
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Range
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Elevation With 1,224 lbs. (555 kg) M1912 AP Shell
Range @ 12 degrees 15,860 yards (14,500 m)
Range @ 18 degrees 19,690 yards (18,000 m)
Elevation With 1,268 lbs. (575 kg) M1924 AP Shell
Range @ 18 degrees 22,970 yards (21,000 m)
Range @ 23 degrees 29,090 yards (26,600 m)
Range @ 47.5 degrees
(as coast defense gun)		 38,749 yards (35,432 m)
Note:  The "Warship Volume X" articles listed below give contradictory ranges for 18 degrees of elevation.  The above table attempts to reconcile the data in those articles.
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Mount / Turret Data
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Designation Two-gun turrets
   Bretagne (5)

Quad Turret
   Normandie (3) and Lille (4)
Weight N/A
Elevation
(see Note 2)		 As completed:  -5 / +12 degrees
Rate of Elevation N/A
Train Forward and aft turrets:  about -150 / +150 degrees
Q turret:  about 30 to 150 degrees on either side
Rate of Train N/A
Gun Recoil N/A
Loading Angle +2 degrees
Notes:

1) Data in this table is for the Bretagne class, data for the others is not available.  These ships were equipped with electric motors driving hydraulic training and elevation gear.  Chain rammers were also electric powered.  Each gun had its own hoist which ran from the working chamber under the turret and a second pair of hoists ran down to the magazines.  Gun loading cages had three compartments, the lower one for the projectile and the upper two each carrying two charges.

2) As originally completed in 1916-17, all turrets had a maximum elevation of 12 degrees with the exception of Lorraine, whose No. 5 turret was given a maximum elevation of 18 degrees.  In 1917 the elevation of No. 5 turret on Provence was increased to 18 degrees.  During reconstruction between 1919 and 1923, elevation of all turrets was increased to 18 degrees and increased again later during the 1920s to 23 degrees.  Coastal artillery emplacements allowed a 50 degree maximum elevation.

3) The amidships turret was removed from Lorraine in 1934-35 in order to fit an aircraft catapult and additional AA guns.

4) During rebuilds in the 1930s, guns originally intended for the uncompleted Normandie class were used to regun the Bretagne class.

5) Turret No. 2 on the Bretagne class was fitted with an 8.20 m (26 ft) rangefinder during various rebuilds in the late 1920s and early 1930s.
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Data from
"Naval Weapons of World War Two" by John Campbell
"The French Dreadnoughts:  The 23,500 ton Bretagne Class" articles by Robert Dumas in "Warship Volume X"
"The Big Gun:  Battleship Main Armament 1860-1945" by Peter Hodges
"Battleships of World War Two" by M.J. Whitley