I have three stripper clips all of which are marked ‘FR’ in an oval cartouche. These are most likely made by Fabrica do Realengo in Brazil.
All three look to be typical 7mm Mauser two lug per side clips however only one of them will fit a 7mm cartridge. The other two differ only by the angle of the ‘recurved’ cartridge retention flanges and by slightly different sidewall heights.
Does anyone know what other military calibres ‘FR’ made?