[DISCLAIMER: The following text is taken from a WWII U.S. War Department
publication. As with all wartime intelligence information, data may be incomplete or inaccurate. No
attempt has been made to update or correct the text. Any views or opinions
expressed do not necessarily represent those of the website.]
The calibers of small arms (weapons with a caliber
below 20 millimeters) are measured by the Germans
in millimeters, whereas weapons with calibers of 20
millimeters and higher are measured in centimeters:
for example, the 9-mm Pistole 08, the 7.5-cm Kanone.
This should not cause any confusion, as the conversion
from centimeters to millimeters is simply a multiplication
Some confusion, however, may be caused by the German
practice of referring to calibers approximately.
The Germans refer to their rifle and machine-gun
ammunition as caliber 7.9 mm, whereas in reality it is
caliber 7.92 mm (.312 inch). Their 8-cm mortar
ammunition is actually 8.1 cm. In many instances the
exact caliber is used: for example, 3.7-cm Pak.