To summarize your options for obtaining a :

For those looking to access a digital version of the Blue Book of Airguns, a verified PDF version can be a valuable resource. A verified PDF ensures that the information is accurate and up-to-date, and can be accessed instantly on a variety of devices.

Be cautious of "free PDF" links on social media or unknown sites, as these often lead to malicious zip files or spam. or a particular historical edition of the book? Blue Book of Airguns 11th Edition