[quote=“Ray Meketa”]Why are shotgun gauges measured in Troy ounces and pounds???
Shotgun gauges in England were measured in Troyes pound because it was the standard weight measure in England in the old time.
in the other countries they were measured in other units
- Marc pound in France (before 1795)
Metric pound after 1795
Kilogramme after (after 1810)
metric pound again after the end of Napoleonian empire
- Toscan, Roman or Genovian pound in Italy
- Austrian pound (Pfund) before 1875,
- Prussian pound before 1875
and so on
Therefore the dimensions of the shotshells cases and barrel chambers and bores were different
Germany switched to the British dimensions in 1904
In 1910-1914 the dimensions were internationnaly standardised (on the paper !) after Bruxelles and Liege conferences
The Internationnal standard is close to the 1904 British standard based on the Troyes pound (it is more complicated in fact because the Brits followed the internationnal dimensions only in 1980)
Some countries used the internationnal standard at once (like Germany) but other countries waited the 1968 Internationnal conference to apply it officially
In France and Italy for exemple both standards were in use till this date
The USA followed the Brits at the beginning and after switched to the internationnal standard in 1920.
USA is still not at the CIP (internationnal) standard even now
(Not very far but they are still some small differences implying different manufacturing from the same shotshells manufacturer depending if the customer is european or american)