Concerning caliber systems, to put it simply, this (American) system (.32 -.38 -.45) indicates the caliber in fractions (tenths) of an inch, resulting in that, if you multiply, for example, .38 by the metric measure on an inch (2,54 mm) you have precisely 9,65 millimeters, which would be the equivalent to a conventional rounded up 9 mm European caliber.
Both .38 and .380 are the same same caliber measure, only that .380 is a later manner to indicate developed ammo properties.
The Brits, as the ones that drive by the wrong side (
) had to have their own weird system; a table where a determined caliber, so called 'bore' (or 'gauge' as for shot guns) corresponds to the number of round balls you can cast per pound of lead.
It could be my eyes or the darkness in the picture, but i don't see in the upper revolver picture in post #6 the little openings in the cylinder for the pins (broche) to point out for the "blunt" hammer to strike ... neither in the Apache also shown, one that looks visibly (?) for cartridge ammo.
But if the upper revolver is indeed pinfire, calling it a .32 cal is somehow unhorthodox, i would say; unless it is about an European production 'chambered' for an American contract.
Perhaps the examples shown in that museum said to simultaneously explode in more than one chambers are the so called pepper boxes, famous for such hazardous episodes.
Concerning the wandering that has been taking place, i don't think is such a crime, as long as the convergent subject is about antique gun business
.
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