By the Way....

Most American manufacturers name their cartridges with little rhyme or reason. They use such a variety of means to name their cartridges that there really is no " rule of thumb" . You simply just have to know.....if you want to.

Germans...and most other continental Europeans...use a somewhat simpler system. An example:

8X57 8mm' s is the caliber 57mm' s is the cartridge case length

9.3X62 9.3mm' s is the caliber 62mm' s is the cartridge case length

And so it goes.....

Good luck!