I follow a set pattern when I name stuff, you've probably noticed. All guns get a nickname so its clear what someone is talking about
Imperial:
Krupp Works: They start with KW- and get the year of manufacture, 2140 for example, and then every new rendition is another number with a U signifying upgrade. 2U Second Upgrade.
ED: Every gun is counted up after the other, it tells you which they invented first. ED-1-2U The upgrade system applies the same as KW.
GA: Follows ED.
CWC: They don't list model numbers or upgrades, its a secret how many designs there are. Nicknames still apply unless its a very specific gun like the only chem sprayer
Arbiters: Follows ED. They don't worry about secrets as only one of you is walking out of a fight alive and it's usually them.
Shi: They all follow the same rules except Kawakami, the clan is listed and then it has a designation by gun type and number. SG3 Shotgun 3. Later guns have bigger number.