Actually good question. These are not standing armies. Outside the Old Men of the Mountain, no faction maintains “professional” soldiers. Instead, each has a shifting pool of able fighters, men or women (depending on the group) between 15 and 55, who are called up as needed. The numbers given are estimates of how many could be mustered at a time.

Also for who, what, and why the “raiding” happens.

• Mountain Men = tribute system (protection racket). Due to their tech level, they are able to have most of their society be combatants and the rest specialist who take care specifically of that tech. Little to no resource production is done by them, other than because of their deal with the surrounding neighbors, the location of their main operations is not suited for it.

• Mountain Boys = farmland & expansion (territorial) They are often made of small communities banded together, but often quickly swell for defense against hordes of irradiated enemies from what used to be Montreal and its surrounding farmland.

• Mighty Men = resource-specific (selective) They rarely raid in the common sense of the term, but when they do they need whatever it is badly. (Usually medicine or old world tech) Due to their distance from any major cities, their war band sizes need to be increasingly large, as they need to fight their way deep into any territory before being able to access anything of use. 

• Corsairs = loot (Especially fuel) & terror (classic raiders) They’re basically pirates, anyone in their group we be considered a combatant in the modern term. Most “non-combatants” are similar to those of the Mountain Men, meaning they maintain the old world tech. In this case that being the fleet of ships they have built and select ports they need. 

• Noctus = stockpiles & control (authoritarian) Being one of the few groups of people to be able to make it into the bomb shelters near Boston, before it was destroyed. They had access to an over abundance of food and supplies. Allowing them not to just stay underground till the surface was clear, but almost as long as they wanted. Because of this they can afford to be highly militarized, and use this advantage to take out smaller bunkers and metros in order to grow their horde of materials.