Shotgun calibers are noted through 'gauges', a term used to identify the inside diameter of the barrel. The term is based on the number of lead balls (these being the same diameter as the gun's bore size) required to equal one pound. The most popular gauge is the 12-gauge which indicates twelve lead balls to equal a pound. Similarly, 28-gauge indicates twenty-eight lead balls to equal a pound. Contrary to caliber sizes used in other firearms and artillery systems, the lower the gauge value of a shotgun, the larger the bore. Thusly, a 28-gauge shotgun sports a barrel much smaller than that of a 10-gauge with the most common gauges bring 10-, 12-, 16- 20- and 28-gauge. '.410' is another gauge value though simply identified by its bore size, much smaller than the preceding 28-gauge. Smaller gauge shotguns are generally suitable for firing by smaller-framed adults and youth.
There are a total of 48 Shotguns (Military and Civilian) in the Military Factory. Entries are listed below in alphanumeric order (1-to-Z). Flag images indicative of country of origin and not necessarily the primary operator.