This is a box of 7 x 57 Mauser armour-piercing cartridges of wartime manufacture. The box reads:
50 armour-piercing Mauser 7 m/m cartridges
Loaded in november 1937
For use exclusively against tanks or armoured cars
The bullets are of conventional design: flat base, CNCS jacket, tempered steel core, lead tip filler. The weight is 9 grams. They are identified by a 15 mm black painted tip.
The headstamp is: (PS 1937). The brass stripper clips are also marked PS.