Dutch beat me to the draw, but I had worked up a reply and I will post it anyway!
Nice label, but you are looking at the loading company’s lot number. The headstamp can be derived from the line that reads “Patrh.:S(Stahl)P249.24.L.39”. So, the headstamp of the cartridge cases in your box should be P249 IXg1 24 39 and be copper-washed steel. The IXg1 is the material code which can not be determined from the label (with the exception of some of the early labels).
Sometime during 1943 the case lot numbers were no longer printed on the labels and you have to physically look at the cases to see what lot is in the box and it is not unusual to find more than one lot in a box.
German 7.9mm labels can be a bit confusing but there is a wealth of information on them.