French 400, 406, 420, and 431mm naval gun designs from the late 30s

[YourChair]

Hello!
The book French Battleships 1922-56 mentions that for the Alsace-class battleship designs, studies for 400, 406, and 420mm guns were ordered. Additionally, a 406mm naval gun was created by the Schneider company for the Soviet Union, and a 431mm naval gun was created: the elusive Canon de 431 mm modèle 1939. Does anyone have any information on these guns?

 

[Non Unified]

Hello!
The book French Battleships 1922-56 mentions that for the Alsace-class battleship designs, studies for 400, 406, and 420mm guns were ordered. Additionally, a 406mm naval gun was created by the Schneider company for the Soviet Union, and a 431mm naval gun was created: the elusive Canon de 431 mm modèle 1939. Does anyone have any information on these guns?

I don't have any new information beyond what you've mentioned here, and I suspect that none exists outside French archives. That said, the bit about the 406mm gun made by Schneider for the Soviets is new to me, where did you hear about that?

 

[Bottleship]

France 45 cm/45 Model 1920.A - NavWeaps

www.navweaps.com

 

[Bottleship]

I don't have any new information beyond what you've mentioned here, and I suspect that none exists outside French archives. That said, the bit about the 406mm gun made by Schneider for the Soviets is new to me, where did you hear about that?

At least during World War I, Schneider produced one 406 mm howitzer of 20 calibers, developed in Russia for the needs of coastal defense. The howitzer was tested, then installed on a railway transporter and used in battle.

 

[Non Unified]

France 45 cm/45 Model 1920.A - NavWeaps

www.navweaps.com

This thread linked on French Wikipedia claims that the 1920 45 cm gun was a joint project with the Army intended to produce a gun for use as both battleship main armament and super-heavy railway artillery, and additionally that the 155mm guns on the Duguay-Trouin class were a product of this same collaboration. No evidence is given but it does ring true to me.