JesseL:
That explanation is a gross under-simplification of the physics involved. The author, of the website you list, acknowledges that sum-of-the-whole of the variables that contribute to catastrophic failure are to too complicated to describe therein. I have read every word of that website (a couple of times) and a good dozen other websites as well. They are all under-simplified.
In the end, the contact that had made the most sense to me was Weatherby, Inc itself. I had specific questions for them regarding my uncle's extreme handloads using "custom-made, stainless steel based .300 Wea. Mag. cartridges". I won't list the precise load details here for concern that someone might actually try to replicate the load in a non-Mark V action.
In short, we are talking apples and oranges. Don't take my word for it. Give Weatherby a call and ask them about the nature and extent of Weatherby's tests of the Mark V action, and if the Mark V .300 Win Mag action will withstand any less than the .30-06 Sprg. I suspect they will advise that the action probably will not be what fails.
Here is my point: One will find it exceedingly difficult to bring a 9-lug, Mark V action in .300 Win Mag to fail. One will find it to be equally difficult to bring a 9-lug, Mark V action in .30-06 to fail. The barrel's threads...now that is a different story. The first thing to give is usually the cartridge’s head/primer pocket, etc. My uncle solved that...custom-made, stainless steel cartridge heads. Yeap, you read that correct. Those employed, the next failure will likely be the cartridge’s walls...that gets ugly because now the cartridge does not have friction on the chamber’s walls. If all parts of the cartridge and bolt holds together, and CUP (copper-under-pressure) rises too high, too fast, the next failure is likely headspace. Like I said, over-simple, apples and oranges, and way, way off topic for the thread.
Doc2005