Simply put, if you think you will get 3900 fps with a 250 gr 30 cal bullet in any rifle, your pretty much willing to buy anything.
I have read that many times, I have the same book. In testing my 300 AX, its pure BS. I can drive a 240 gr bullet to over 3200 fps pretty easily. If I push her harder to around 3300 fps, the primer pocket will come loose, and thats in a Lapua case.
I have never seen a Rigby case that was anywhere near as strong as the Lapua, now you hear all the time that they use some exotic europissin brand of brass that will handle 120,000 psi which is a good thing, because you would need most of that to get a 250 gr bullet to 3900 fps.
Just for a reference, my 338 AM will get the 250 gr bullets up to around 3700-3800 fps in that length barrel and thats with 155 grains of powder.
Anyway, I have been amazed this has not been pulled from the book. Another one of those, I would have to see it to believe it and I would want to be well protected from flying rifle parts.
This round is no different then the 300 Kahn which is a 30-378 Wby with a conventional angled shoulder instead of the double radiused shoulder. It will not do what is reported, not even remotely close to this.
Kirby Allen(50)