I thought I posted a review of a long time ago but maybe not. In any event I re-read the book recently and it came across much better the second time around.
Vaughn was a retired engineer who took a scientific approach to shooting. It's a nerdy book, so if you have a background in science or engineering you'll enjoy it.
If you're not a nerd then you probably won't get much out of it.
The first time I read it, I was put off by Harold's personal style. He came across as cocky yet didn't present a lot of data to back up his claims -- we just had to take his word for it. For example, I don't think there is a picture of a single target in the entire book.
However, in fairness to Harold it was probably the editor's decision to leave out a lot of the test data. The fact is, boring data does not sell books. Likewise there is very little data in Colonel Harrison's "Cast Bullets" book even though the Colonel claimed he conducted thousands of tests in the course of writing his book. In both cases, the editor probably left out most of the data to make the book more readable. I don't like it, but that's the nature of publishing.
The second time I read it, it didn't come across as particularly cocky except in a couple of places. One example is the section on his 6 Degrees of Freedom Exterior Ballistics (6DOF) computer program. He mentions repeatedly that the 6DOF program is the greatest thing since sliced bread, but then never shares the program with the reader. Well, what good does it do us to hear about a computer program that we have no access to? It comes across as showing off -- "hey look at me, I wrote this cool program, but you can't have it, nah na nah nah"
That said, I enjoyed the heck out of the book. It made me think. Even when I disagreed with Harold, he still made me think about things that I hadn't thought about before.
The biggest single part of the book that I question is Vaughn's claim that Spiralock barrel threads and torqueing the hell out of the barrel improved accuracy. I can't argue with his logic or with his data, such as it is, but the bottom line is that lots of benchrest shooters don't use Spiralock threads and don't torque the hell out their barrels and yet it doesn't seem to hurt their accuracy.
I'll highlight a few of the book's points that are particularly relevant to cast bullets. On page 170 he identifies bullet imbalance as a major limitation to accuracy and even gives us a nice equation to quantify it. Since our cast bullets will never be as well balanced as a jacketed bullet, I think that particularly concerns us.
The takeaway is that dispersion due to imbalance increases proportional to velocity -- no wonder it's so hard get high velocity cast to shoot well !
Another important takeaway is that we can minimize the dispersion due to imbalance by using a slower twist.
That's not a new discovery, but Vaughn does a great job of cutting through the myths surrounding RPMs and instead explains it in precise, scientific terms.
Another Vaughn point that is relevant to cast bullets is that bullet friction is much ado about nothing, and that bullet lubes actually reduce velocity to the extent that the lube interacts with the hot gases and cools the gases (p. 231).
All in all I admire the heck out of Harold and wish there were more shooters like him in the world. By the way, the book is out of print and has become a collector's item. Used copies start at $500 and go up to $6000.