Guns, Firearms, and Modern Weapons in Isekai
Manga
Since I've had trouble finding it myself, here's the collection of manga where the main character(s) have the advantage over the Sword and Sorcery world by flexing the most powerful magic of all: GUN.
Not saying they're all good, but I just want to collect as many in one place as I can.
Not saying they're all good, but I just want to collect as many in one place as I can.

Manga, ? vol, 2020
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IIRC, MC introduces guns when making an alliance with a neighboring city-state.

Manga, ? vol, 2021
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Manga, ? vol, 2018
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Like Gate, but instead the Entire country of Japan is transported to another world, with various civilizations ranging in power from Medieval to WW1 level aircraft.

Manga, ? vol, 2020
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Manga, 5 vol, 2019
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