Alright, we've got documents threads in aerospace and tanks, we need some for small arms now too.
Small arms technology lags other fields by decades, by here at Sturgeon's House, it only lags by months!
General Design Theory Treatises:
First up is a link to George M Chinn's The Machine Gun. This is the premier English-language book on automatic weapon design theory. Also, because it was a US Government publication, it is legally available for free. The book is mainly focused on th