If you wonder what Tanya means with "the Trenchgun is banned", this refers to a situation that happened in World War I.
When American troops arrived in Europe in 1917, the soldiers also brought along shotguns of various kinds.
The pellet bullets cause devastating damage, especially to living objects (animals and humans) due to the large amount and the area they cover.
In the so-called Hague Rules of Land Warfare, which was created in 1907, there is also a clause expressly prohibiting the use of such weapons, which inflicts unnecessary suffering and pain on an enemy soldier.
These include shotguns, but also other types of ammunition and weapons, such as. Dum-Dum projectiles.
Article 23 of the Hague Convention on Land Warfare:
Apart from the prohibitions set by special contracts, the following is prohibited by name:
e) the use of weapons, projectiles or substances capable of causing unnecessary suffering,
Overall, Articel e is one of 8 rules listed under paragraph 23.