Anyone know any good place to download firearms primary sources in PDF form?

Already have Chinn's machine gun and Hatchers notebook. Looking for something similar about suppressors.

>>63813649 (OP)
This is an older book but it's a *really* good one. If there ever was a "gun bible" this would be the Old Testament and Chinn would be the New.
https://openlibrary.org/works/OL3156857W/The_gun_and_its_development

Sixguns by Keith is another great source that's worth tracking down. The links I knew for downloads are no longer any good, but you can "borrow" it from Openlibrary or the Internet Archive.

The book focuses on revolvers but it has a lot more information than just that, it also has a lot on hunting, handloading, defensive shooting/gun fighting, shooting handguns at long range, trick shooting, and so on.

Defcad library has some resources and it's easily accessible and free.
https://defcad.com/library/?sort=created_desc&artifact_type=Document