The only mention of guns in canon that I can recall is at the start of Prisoner of Azkaban, where the muggle side of the Sirius Black scare mentions him as armed and dangerous, and the Daily Prophet agrees that muggles are saying he has a gun, which they describe as being something like a muggle wand that they can use to attack one another.
I assume that a great many wizarding children went on to imagine the muggle world as some very interesting variant on the stereotypical Wild West, where "boomstick" was probably a better description of a shotgun than usual.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 98. The previous thread is at nearly 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system.
Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: