Firearms in space make practical sense. Exploding gunpowder can be used in hard vacuum because gunpowder produces its own oxygen. As long as its a closed cartridge, it will fire. Flintlocks, and percussion therefore, make little sense offworld.
Old west guns in a space frontier setting also makes perfect sense. They are designs that are proven to work, and they might not have access to expensive, advanced or automatic weapons that would be more available on core worlds.
Comparing the LeMat to the Mauser Broomhandle is apples and oranges. They're both unique guns and no amount of dressing up will change that. Your preference of one or the other is directly proportionate to the fandom you support.
I am in no way a Star Wars fan. My reasons for not being one are mostly the fans. That said, I have no quarrel whatsoever with any fan, or fandom on this board. I came here to learn, and share.
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Ugliest costume? I think the male miniskirt from the first season of TNG was ugly.