Funny. I kinda thought it was the U.S. Constitution that sold us on guns.
No, and until 2008's Heller vs DC decision, private gun ownership was not considered an established right. America's status as a gun-loving nation is a relatively modern invention, and entirely one devised by gun manufacturers. It's working, too (and with somewhat predictable results).
Here's a book that takes a closer look at how guns took on this sort of mythic role -- more special than other tools and appliances -- in American identity:
https://www.pamelahaag.com/books/gunning-of-america/