Citizen K also posted this on the AVA from the Blue Book of Airgun Values and the following link on a condolences website from Beeman's wife, Toshiko, which mentions her husband's death:

It is with much sadness that we want to share the passing of a friend and airgun legend, Dr. Robert Beeman (1932-2021). Mr. Beeman was a crucial part of each new edition of the Blue Book of Airguns. He was an innovator, enthusiast, and true leader in the airgun community and his contribution to the sport and love of airguns will be truly missed.
"In many ways the length and breadth of the Airgun section comes as a result of one man's work, Dr. Robert Beeman, the father of the American adult airgun." - Steve Fjestad, 1998.

https://www.legacy.com/us/obituaries...ary?id=9092924


Steve Fjestad with Robert Beeman: