Friedrich Wilhelm Schembor
In the contribution at hand the author describes how the calibres of rifles and bullets were fixed 200 years ago. Everybody interested in old rifles knows the problem that the calibre, which is defined as the inside diameter of the barrel of firearms or as the diameter of bullets, thus supposed to be a measure of length, was given as a measure of weight. In order to answer the question what is meant by calibres of former times such as pound and lead, and how these calibres were calculated, it is necessary to look into the fixing of the dimensional and weight systems of that time in general. During the examined period an enormous number of different units of measure were used simultaneously. Every state, every country, every earl, every count, every ruler of a piece of land, no matter how small it was, had his own units of measure. These units of measure had the same names in the different territories, but they comprised different sizes and quantities. So, if one travelled around, one had not only to grapple with the various currencies, but one had also to be wellinformed about the various different units of measure. Here the introduction of the metric dimensional and weight system put things right, which had been valid in France since 1799, but which became effective much later in all the other countries. In Austria, for instance, the metric system was introduced optionally by the act of 23^{rd} January 1871 not earlier than 1^{st} January 1873, and became compulsory on 1^{st} January 1876. At that time the Austrian measure of length was the fathom. One fathom consisted of 6 feet (shoes), which again were divided into inches, lines, points and quints. The calibres of rifles and bullets were defined correspondingly. The basis for defining the calibre of rifle bullets was the diameter of a cannon ball of exactly one pound weight. In the years 1816 and 1817 extensive experiments were carried out with the models available in the High Artillery Office, which resulted in quite usable “regulated” diameters for bullets, pellets, shells and bombs, for the bores of rifles and carbines, and for the diameters of the appropriate measuring instruments, such as the gauge and sight spikes as well as the bullet and cartridge gauges introduced in the AustroHungarian artillery. By presenting and discussing some original sources which have not been noticed so far, it has become possible to demonstrate how these relevant data were found out 200 years ago.
