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These impressive self-propelled heavy guns, the chassis of which designed by Rimailho (technical director of Saint-Chamond), have been adopted in 1918 (194 GPF and 280 TR short howitzer). They were scheduled for the 1919 offensive which never occurred. The program also included a batch of 220 (short) M 18 Saint-Chamond and 155 GPF on Saint-Chamond, plus a completely different self-propelled chassis by Schneider, carrying a 220 L Schneider M 17 gun.
Rather large orders were placed for these heavy equipment, but most of them were cancelled in November 1918 " pour cause de victoire". Were actually built, on the Saint-Chamond carriage : - 1 x 120 long gun (early 1917 prototype) - 1 x 220 short howitzer (prototype) - 1 x 155 GPF (prototype) - 50 x 194 GPF (one regiment mobilized in 1939) - 25 x 280 TR 14 (one regiment mobilized in 1939)
Plus, on the other type of chassis, produced by Schneider : - 5 x Schneider 220 L (not mobilized).
Afaik. Also some artillery variants of the FT17 were considered .
Certainly the FT17 Batterie the support with a larger turret with a short 75mm would have been build in great numbers (970). But this counts by barely as self propelled artillery i guess.
The there was also a FT 17 with a long 105 mm gun mounted rearwards, but i'm not sure this was accepted for production.
the 194 mm GPF was indeed used by the german army in WW2, as 19.4cm Kanone 485 (f) auf Selbstfahrlafette , 3 examples were used by Germans in Russia circa 1942 by 84th Regiment of Heer Artillery. The heavier 280 mm mortier version was also captured but I have not any references. Further, intersting data in http://maquetland.com/v2/index.php?page=vision&id=353