Originally the anti-tank casemates of the Ouvrage de Cindey were armed with 4,7 cm guns mounted on a so-called "affut à flasques". However in the second half of the fifties they were replaced by more powerful 9 cm guns model 1950 (9 cm Pak 50). They defended the narrow passage west of Saint-Maurice. One of right you can see a high explosive shell.

During World War Two it became already very clear that light guns, like the 4,7 cm guns used in the Swiss forts, were not powerful enough the penetrate most tanks in service. Therefore it was decided to develop a new gun which was based on a Belgian design of the company Mecar. This was a low-recoil weapon which was also suited as a field guns. Therefore it had a relatively thin barrel which fired a shell with a maximum velocity of 600 m/s.