With respect to the case; its function is to protect the pellet and the powder, three elements are necessary for its manufacturing:
• A tube, usually plastic.
• A metal head, which determines the category or type of cartridge.
• The inner lid, which helps a perfect linkage between the plastic tube and the metal head.
The mounting of these three elements is done by means of pressure so that, in order to separate the metal head from the case, it should undergo a pressure of over 100 kilos. Only the high technology that allows the production of billions of these elements ensures perfect uniformity.
Following former British rules, they are greater when their number is smaller, and vice versa: one of the 9 is 2 millimeters in diameter by 2.75 of one of the 6. Central European countries, especially Germany, Austria and Switzerland, resort to its diameter in millimeters for identification; this makes sense to clearly know the size of the buckshot and to unify criteria because, for example, the number 8 in Italy measures 2.30 mm, 2.25 in Spain and 8.20 in Britain.
Generically, you should be using a soft buckshot to hunt with maximum 1.5% antimony in its composition; to throw to the plate, as hard as possible, with a minimum of 2.5% and up to 5% -. Some fine pellets, 9th or 10th, will lose a lot of speed once they leave the barrel, as their specific weight is very small and the speed tends to decrease rapidly.