Glossary

Calibre with rifle cartridges: In order to be on the safe side choosing the correct calibre, it is necessary to consider the complete calibre designation with all additional given indications.
Example: 7 x 64: The first number “7” indicates the bullet diameter, the rounded down calibre of the rifle barrel, respectively of the bullet in millimetres.
The number “64” indicates the case length, likewise in mm.
In English speaking countries, the calibres are usually indicated in inch measurements (1 inch = 25.4 mm), without considering the case length.
Instead, there are often indications to the history of origin of the calibre.
The “30-06” for example is a calibre 0.30 inch and the year of construction is 1906.
Often the name of the manufacturer, who put the cartridge on the market for the first time, is used in the calibre designation, like with the 6.5 x 65 RWS or the .30R Blaser.

Gauge with shotshells: With shotshells the gauge approximately indicates the number of the uniform balls that are cast of pure lead, which altogether weigh one English pound (=453.6 g).
Therefore, 12 gauge corresponds to the diameter of a soft lead ball, of which 12 of these balls weigh one English pound. The exact diameter is specified in the dimension tables of the firing laws.