solarshooter
WKR
Well I bought Siewert's book (caveat, I'm only halfway through), and unfortunately it is much the same as his podcast appearances. A series of statements and anecdotes with little to no theory, data, or discussion of test methods and results. It reads more like a memoir than anything scientific. Yes there are interesting findings and analysis discussed, but it is more a list of results and career accomplishments than it is a scientific explanation of ammunition.I misspoke in my post above. I follow his theory, I just didn't see him go in depth or explain any test or evidence of this theory being correct.
This book https://archive.org/details/RifleAccuracyFactsFullV1.0FirstFullScan/page/n53/mode/2up contains theoretical, simulation, and experimental results that indicate that barrel modes do indeed exist and impact precision.
Like I said, I think I need to read Jeff's book to really get into the meat of his theory and evidence. I just haven't yet.
That being said, his experience seems very high-level, so I'm not saying that his presented conclusions and facts are wrong. Just that the book is not very enlightening on how he arrived at these conclusions or tested various hypotheses. Contrast that to Litz's books, where he shows the entire scientific process from problem statement to hypothesis to test to conclusions, as well as often including lots of raw data.
PS: Siewert name-drops the Vaughn book I linked above in his foreword - and it's the only book he does so with.

