The best resources for arms and armor websites
The metmuseum has an extensive department for arms and armor. Their collection and knowledge on this topic is outstanding and the best place to start for you if you want to understand this topic.
https://www.metmuseum.org/about-the-met/curatorial-departments/arms-and-armor
Heritage auction is the number 1 auction house for militaria arms and armor. Very few auction houses has the amount of items as they do.
https://historical.ha.com/civil-war-militaria-arms-and-armor/
https://www.ebay.com/sch/i.html?_nkw=arms+and+armour&ul_noapp=true