what i always found interesting were the companies that had nothing to do with military or firearms during peacetime, making guns for the war.
like union signal & switch, singer sewing machine, rockola jukebox, IBM, & if i'm not mistaken, remington rand was a typewriter company too right?
International seemed to make everything at one point, war time or not. my grandparents still have an old IHC fridge in their garage.
slightly off topic, but i remember my all the ceramic stuff in my high school chemistry lab was made by Coors brewing company. and god knows how long ago.