The French navy used the Model 1906 on the last of their pre-dreadnoughts and the Model 1906-1910 on the first of their dreadnought battleships. Both models are listed as being used as railway ordnance during World War I.
Construction was a complicated built-up design, similar to other French heavy guns. The two model types were similar, differing in minor constructional details. Actual bore diameter was 30.5 cm (12.008").
|Designation||305 mm/45 (12") Model 1906
305 mm/45 (12") Model 1906-1910 1
|Ship Class Used On||Model 1906: Danton class
Model 1906-1910: Courbet class
|Date Of Design||1906 & 1910|
|Date In Service||Model 1906: 1911
Model 1906-1910: 1915
|Gun Weight||Both: 120,590 lbs. (54,700 kg)|
|Gun Length oa||558.07 in (14.175 m)|
|Bore Length||Model 1906: 540.55 in (13.730 m)
Model 1906-1910: 536.42 in (13.625 m)
|Grooves||(90) 0.071 in deep x 0.118 in (1.8 mm deep x 3 mm)|
|Twist||Uniform RH 1 in 43|
|Chamber Volume||12,921 in3 (211.787 dm3)|
|Rate Of Fire||about 1.5 - 2 rounds per minute|
- ^The unusual designation "1906-1910" for this gun was to indicate that its design was basically the same as the Model 1906 gun but that the design had been modified in 1910.
|Projectile Types and Weights 1a||Model 1906 Guns
APC Model 1906: 960 lbs. (435.5 kg) 2a 3a
Both Model 1906 and Model 1906-1910 Guns
|Bursting Charge||APC Model 1906: 25.0 lbs. (11.32 kg) Melinite
APC Model 1910(?): 36.3 lbs. (16.46 kg) Melinite
HE Model 1916: N/A
|Projectile Length) 6a||APC Model 1906: 40.923 in (103.94 cm)
APC Model 1910(?): 40.923 in (103.94 cm)
HE Model 1916: N/A
|Propellant Charge 7a||APC Model 1906: 320 lbs. (145.0 kg) BM17
APC Model 1910(?): 274 lbs. (124.3 kg) BM17
HE Model 1916: 280 lbs. (127 kg) BM15 8a
|Muzzle Velocity||Model 1906 with APC Model 1906: 2,559 fps (780 mps)
Model 1906-1910 with APC Model 1910(?): 2,569 fps (783 mps) 9a
Both Model 1906 and Model 1906-1910 with HE Model 1916: 2,789 fps (850 mps)
|Working Pressure||Both: 16.5 tons/in2 (2,600 kg/cm2)|
|Approximate Barrel Life||300 rounds|
|Ammunition stowage per gun||Danton: 81 rounds
- ^A Note on Sources: The secondary sources listed below differ greatly on the details for the ammunition used for these guns. John Jordan kindly provided me with information taken from French official documents and these values are used throughout this section.
- ^Weights for the APC 1906 differ in official documents with a weight of 970 lbs. (440 kg) also being seen.
- ^The APC projectiles for these guns were classified as obus alourdi (heavyweight shell). The base fuzes for these projectiles had a dual delay mechanism which in theory enabled them to engage both thin-skinned and heavily armoured targets. They therefore replaced both the separate APC (obus de rupture) and SAPC (obus de semi-rupture) shells carried by earlier battleships. These dual delay base fuzes did not work particularly well but their performance was improved over the years.
- ^Weights for the APC Model 1910(?) differ in official documents with a weight of 952 lbs. (432 kg) also being seen.
- ^As an attempt to increase the range of these guns against land targets, in 1917 the Navy adopted an HE shell that had been developed by the Army for use with its railway guns. The official designation of this shell was FAB Guerre Mle 1916. About 70 of these shells were carried by each ship.
- ^As these guns had a steep twist (1 in 43), the shells for them had relatively short bodies.
- ^Propellant charges were in quarters for both the Model 1906 and the Model 1906-1910 guns. A Note on Sources: "Naval Weapons of World War One" incorrectly says that the charges for the Model 1906 gun were in halves.
- ^The propellant load for the HE Model 1916 projectile was reduced from that for the APC Model 1906 as the HE projectile had thinner walls than did the APC Model 1906 projectile and could not handle the added stress of a full charge. This lower charge weight still gave the HE Model 1916 a much higher muzzle velocity and a longer range than either of the APC projectiles.
- ^Muzzle Velocity for the Model 1906-1910 gun using APC Model 1910(?) differs in official documents with an MV of 2,618 fps (798 mps) also being seen.
- Official Projectile Designations:
Actual French designations APC Model 1906 OPfK Mle 1906 APC Model 1910(?) OPfK Mle 1910(?) HE Model 1916 FAB Guerre Mle 1916
- Projectiles had three driving bands.
- These projectiles were not given dye loads during the 1930s as they did not have a ballistic cap to accommodate them. This was probably because when the French Navy was implementing dye loads in the late 1930s, the two surviving (active) ships of the Courbet class were both being used as gunnery training ships and not as front-line units.
|12 degrees||15,860 yards (14,500 m)|
|12 degrees||14,760 yards (13,500 m)|
|23 degrees||28,430 yards (26,000 m)|
|12 degrees||18,260 yards (16,700 m)|
|Weight||1,236,793 lbs. (561,000 kg)|
|Elevation||Model 1906: -5 / +12 degrees
|Rate of Elevation||3 degrees per second|
|Train||about +150 / -150 degrees|
|Rate of Train||4.5 degrees per second|
|Loading Angle||Between -5 and +8 degrees|
- These mountings were all-electric powered with spring run-out.
- These guns used a parallel-action loading tray which at its highest position was in-line with a fixed waiting tray. The shell cage delivered the projectile to the waiting tray from where it was pushed over to the loading tray. The loading tray then sank down in line with the breech where it was locked so as to follow the gun as it elevated. When the breech opened, the tray could be swung over into the loading position where a spring-powered rammer pushed the projectile into the breech. The rammer spring was recocked by the recoil of the gun. Propellant charges were loaded by hand.
- Four ready projectiles and charges for each gun were stored in the turrets.
- Each turret had a shell and propellant handling room at the base of the hoist and a second handling room at the bottom of the rotating trunk.
- Each turret had a turret captain, a trainer, two layers, four breech workers, two hoist operators, six crewmen to work the air blast, waiting trays and to load the ammunition.
"Battleships and Battlecruisers 1905-1970" by Siegfried Breyer
"Naval Weapons of World War Two" by John Campbell
"Identification of the Parameters of Naval Artillery" by K. R. Crawford and N. W. Mitiukov
"Naval Weapons of World War One" by Norman Friedman
"The Big Gun: Battleship Main Armament 1860-1945" by Peter Hodges
"French Battleships: 1922-1956" by John Jordan and Robert Dumas
Special help from John Jordan
23 May 2006 - Benchmark
28 March 2012 - Updated to latest template
03 June 2016 - Converted to HTML 5 format
07 April 2018 - Reorganized notes, added details on the differences between the Model 1906 and the Model 1906-1910