M44----k31

I was digging through my rifles today and I found my Swiss Mauser M38 and my K31.
Now I know the 38 takes 6.5x55 . The k31 takes the GP 11 in the 10 white round box right?. What is the complete caliber? My box says 7.5mm Thanks.... i AM GUESSING 7.5X55

My RCBS box says: 7.5mmx55 Schmidt-Rubin.

Your M38 is Swedish, not Swiss. I see that all the time.

Yes the k31 takes the gp11 which does come in the ten round white cardboard boxes. the full name of the caliber is the 7.5x55 Swiss.