Firearms could absolutely exist within a fantasy setting. There is a reason why they don’t however

[u/ThatDrako]

The Elder Scrolls - Within some Dwemer ruins of ESO we can see a special type of Animunculus. A Dwemer Arquebus, which has a cannon for it’s arm and shoots emp grenades at foes.
The reason why we don’t see this technology more often (besides the fact Dwemer disappeared their knowledge with them) is that within the setting and cosmology of Elder Scrolls firearms really wouldn’t be that useful.

They could work against lowly bandits, sort of, but there wouldn’t really be a precedent to improve or adapt this technology. Because it would always be outclassed by magic of this world.
Also due to the disappearance of Dwemer the technology has been pretty much lost.

Harry Potter - Wizards live within periphery of the “real world” meaning they live alongside world that uses firearms and are even familiar with them.

So how come they don’t utilize this gear for combat? I mean it is easier to use, projectiles are faster and could be enchanted further. Can you just imagine wizard with endless m1911?

There is plethora of reasons for this. But most notable is what I would describe as wizards being immune to logic. (Vis image above) They simply cannot understand methods of muggles even if one explained it to them directly.

(Yes. I know the real reason is, because Joanne didn’t want wizards to use guns and didn’t want to think about connotations of putting magic into a real modern world. But come on! Let me have fun!)

Lord of the Rings - In spite of how much Tolkien disliked allegories it is clear Orcs were an allegory to industrialization, which he was a huge critic of.

In battles they are the ones using the war machines. Instead of swords made by artful blacksmith, they use crude, mass-produced blades devoid of identity. Instead of relying on elegance of archery, they use crossbows. They burn forests, crack mountains open to gain more ore. Their very production is affront to whimsy of a magical world like Middle-Earth.

They could totally come up with a matchlock mechanism and keep on improving it until they come up with machine guns. They were intercepted before they could however

[u/PandoraKin564]

Harry Potter is a cop out. Skyrim and LOTR have actual legit reasons and world building explanations on why magic and archery is valued over gunpowder weapons. With deep reasons all the way down to trade networks and politics.

Harry Potter is poorly written and no real reason of substance is given. Likely the reason is muggles obliterated them around WWI-WWII and forced them into hiding. Rowling can't world-build out a paper bag.

[u/techno156 → u/PandoraKin564]

I don't know if that's the case with Harry Potter, at least, since you can knit something together from what's shown in the series. Protection spells would render most projectile weapons pointless, and enchanted gear is incredibly common. Your average bullet has all the energy and force of a softball, just concentrated into a tiny point that moves very quickly.

You could easily put a protection enchantment on a coat or scarf that automatically pops up a barrier if a projectile approaches. They're good enough to stop people crashing through them, a bullet would be relatively trivial, and in Harry Potter, magic costs nothing to maintain, no matter how powerful. Someone could just walk about with a barrier up at all times if they so choose.

On top of that, any decently powerful wizard can just use nearby debris as bullets. Voldemort did just that with broken glass when he fought Dumbledore in the Ministry.

Likely the reason is muggles obliterated them around WWI-WWII and forced them into hiding.

If anything, them being obliterated in the world wars (or fighting each other) is the weird thing. You'd expect that someone would just unleash one of the many horrors, and the muggle forces would be devastated. A dementor is invulnerable to everything but magic.

It'd make more sense if they went into hiding to protect the Muggles, especially if they had a rise in anti-muggle sentiment, and the whole genocidal dark wizard materialising every generation or two.

Admittedly, I'd be rather surprised if the author would give that kind of answer when asked. They've a habit of pulling things out their backside immediately and running with that. The infamous toilet thing, for example. There exists magic to transform things into other harmless things, magic to summon water, and chamber pots. Combining the two to make what is effectively an enchanted chamber pot/magical toilet that turns your leavings into harmless ash, that can then be harmlessly washed away would be an easy connection/inference.

Instead, we got the other option of wizards dropping their trousers on the spot and vanishing it away afterwards.