: This is one of the most extensive resources. You can find high-quality scans of books like Weapon: A Visual History of Arms and Armor and various volumes of the Gun Digest series.

For technical data, military manuals, and official histories, these sources are highly reliable. Project Gutenberg

: A project of the Internet Archive that allows you to "borrow" digital copies of specialized books, including those on firearms design . 2. Specialized Military & Historical Repositories

: Focuses on public domain works. It includes classic titles such as Armour & Weapons .

These platforms host historical treatises, encyclopedias, and classic texts whose copyrights have expired.