What do the numbers on the shell base mean?

The number on the bottom of the cartridge case is the manufacturer and year code of the bullet. If the two sets of numbers are in the same direction, the factory code is above and the year code is below. If there is a decimal mark, then the decimal point is the year code. If the last digit of a set of numbers is "1", it represents the manufacturer.

Shell is the basic component of a bullet or shell, and its function is to connect the bullet, primer and propellant into a whole, so as to ensure the positioning of the whole bullet in the bore, prevent the propellant from being affected by external conditions, and prevent the gunpowder gas from leaking from the tail of the bore and directly ablating the bore during shooting.

Extended data:

In order to strengthen the ductility of shell casings and prevent them from being stuck and difficult to eject, many early shell casings were made of copper-iron alloy and other materials. With the gradual development of metallurgical technology, great changes have taken place in domestic metal quantity. At present, shell casings are mostly made of copper clad steel or low carbon steel. The molding process is integral casting and cutting technology. Different guns use different shell lengths, inclinations, calibers, low slots and fire holes.

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