These books do contain some good articles, though some were probably quite controversial when written and may remain so. Ackley was a good no-nonsense writer, far better than many we have today. I haven't read any of his material in many years, but seems like he worked for GUNS & AMMO for a number of years when it was a good magazine. He did a lot of experimentation and reported the facts based on the results of his work.
This was not half-done amateurish Internet-type material.