First off, I want to be very clear that this is not a rant and I am not angry or upset. I mention this because I know from experience that sometimes I can come off as such and I want to assure you this is not the case right now.
I 100% appreciate and am thankful for the people who made me think of this and do this research because I simply did not think about it and that was a big mistake on my part. This is definitely something I will try to work into the story where I can and if I ever do a third rewrite in the future will make sure is included.
I wanted to type it up separate for now however to appease people and help shore up loose ends. Plus, I learned a lot on these topics that I did not know and it was super interesting. I spent somewhere around two hours reading as much as I could on the topic before gathering what I deemed enough information for my purposes.
I will endeavor to prevent things like this from happening in the future though and I really am sorry I left such a big gap in the storytelling.
Ok, so I am sure if someone does enough research and is a subject matter expert they can find a way around this, but to me, this seems like a reasonable list as to why the town isn’t mowing the goblins down with a bunch of M4A1s.
1. Identifying the constituent parts is difficult if you don't recognize them or know where they would be concentrated. How many people reading this could tell me where to find a reasonable supply of the various chemicals? Who would even recognize them? If they can be made out of common supplies that might still be in towns, how many of you know how to make it? 200 years have passed at this point and not many regular people know this information, let alone those that survived and passed it on somehow. Internet is not a thing and many books were destroyed early on. How many houses happen to have books on early gun creation sitting around?
2. Without a source of sulfur, which likely wasn’t high on the priority list to mine for when trying to survive in this type of world, gunpowder is pretty hard to ignite. Sulfur lowers the ignition temperate by over 100 degrees which is why it was so important for guns to become useful in the past. Without the sulfur igniting it requires an ignition mechanism many times better than flintlock and that would not be reasonably available to these people.
3. The method for making it without sulfur is HARD as well and it would not be unreasonable for the few who might be trying to still fail at perfecting it enough for practical use.
4. Existing stockpiles of guns and ammunition would be largely depleted or useless. Most ammunition has a shelf life eventually before becoming useless or dangerous and 200 years is a very long time, especially if it was not stored well considering all the destruction the plant growth caused.
5. Since it would be hard to find non-electric powered tools for the manufacturing process they would need to make dedicated tools for it from scratch and that would take quite a bit of time and also the tools required are specialized enough that they would have no other practical use.
6. Creating primers is way too high tech to do so without real modern technology
7. Even if they did somehow know about and find all of the various supplies to make it, making black powder that is actually useful is a VERY exact science and took a lot of time to iron out. It would be hard to dedicate time and effort to this when people can defend themselves using Ki, enchanted items and scrolls from the dungeons which they need to keep clearing on a regular basis in order to keep the monster populations down.
But why don’t they have working electricity, machinery, refineries and so on after so long?
1. Any batteries or methods of power storage are trash after the amount of time that passed whether they had been used or left to sit. I did the research on this to be sure.
2. Prior to the industrial revolution, electricity didn’t really have a lot of uses. There is not much work that needs to be done at night when you need to be sleeping and lighting indoors can be done much easier with fireplaces, lanterns and so on. In a situation like this people would prioritize and realize that electricity is not needed for survival at the moment.
3. Again, not many average civilians have the proper knowledge to set up an electrical system from scratch even if everyone knows the bare basics of how it works. How many of you are confident you could make your own electricity generation if dropped in an abandoned and destroyed city? Let’s say you have 20 people willing to follow you (early on there would be many small groups, people all want to be In charge), how about now? 100 people but still just you having the knowledge of how to do so?
4. Old school water mills and such exist of course for certain uses but using them to generate electricity, let alone storing it, requires technology well beyond what a small isolated community would be capable of producing.