In 1954, the Unique company (MAPF) in Hendaye France rebuilt a batch of 800 Berthier carbines into .22LR caliber for use by the Sûreté Nationale (later renamed the Police Nationale). These were to be used for training and also issued to prison guards. Both 1892 and 1916 pattern carbines were used, and so the CRS .22s can be found both with and without upper handguards. They were fitted with 5-round magazines from one of Unique's pistols. The change of the firing system from centerfire to rimfire was rather cleverly done, with the new barrels bored at a slight angle to obviate the need to change the firing pin geometry. This did require shaving down the cocking piece and changing the sights, however.