Would I expect a DM to accept a peasant railgun? No.
Would I love to play in a campaign where we are dungeon-crawling scientists who are investigating the theory that we are actually living in a poor simulation? Hell yeah. Just imagine your d&d university admissions departments working out that people somehow can be sorted precisely on a scale of -5 to +5 in terms of natural competency for any skill…
It was abandoned partway through a second "series", but it's still out there: Harry Potter and the Natural 20. Fanfic, obviously, but a very amusing take on how you could theoretically break D&D by applying Potterworld physics (or vice versa).
The peasant railgun was a footnote to one of the early chapters. Author specified that he would never, ever allow most of the munchkin tricks he wrote about in a game that he DM'd, but since crazy munchkin tricks are the source of a lot of the humor in the writing, he left them in the fiction.
Would I love to play in a campaign where we are dungeon-crawling scientists who are investigating the theory that we are actually living in a poor simulation? Hell yeah. Just imagine your d&d university admissions departments working out that people somehow can be sorted precisely on a scale of -5 to +5 in terms of natural competency for any skill…