A few comments on this thread in general:
Many pressure signs, such as loose primer pockets and ejector-hole marks on case heads, often don't appear until around 70,000 PSI, which is one reason early published data was often hotter than todays, and the big reason wildcatters often get higher velocities out of cases that don't hold much, if any, more powder than factory rounds. As an example, it's why most 7mm STW handloaders got 3600+ fps with 140-grain bullets when the round was still a wildcat, but after Remington made it a factory round the hottest factory ammo was listed at 3400.
It's very interesting to read that info about the 7mm STW. That caliber was responsible for a severe injury I saw in my ER about 1997, might have been 1998, and it changed the way I reload metallic cartridges.
The fellow I treated had a Remington 700 chambered in this caliber. He was using load data from magazine articles (internet reloading info was nonexistent, or at least very difficult to find in those pre-Google days), and was doing load development at his home rifle range. His rifle blew up on the bench, and according to him it was the third load in a string of 3 shots with that powder charge, which he stated was the max charge listed. He was adamant that the previous 2 bullets had exited the barrel, as he was marking the POI of each shot in his load notes with his spotting scope. The rifle blew open just forward of the chamber and all the way to 3-4" from the muzzle. My patient told me there had been ZERO "pressure signs"... no flattened primers, no case bulge, no difficulty lifting the bolt.
The fellow told me he had been using the published data from Shooting Times magazine, so I presume this may have been the original Layne Simpson data, which as you point out was quite a bit hotter than the manuals later came out with. Anyway, it blew up his left hand pretty badly. His thumb was ok but all four fingers were blown open and fractured. Tendon damage was severe. I numbed him up, cleaned him up, and sent him on to a hand surgeon. He wrote me a thank you note a few months later and told me he'd got back pretty much full use of the hand, but it still hurt all the time.
I had used "pressure signs" in load workup up to that point, but after that 7mm STW injury case, I resolved to stick to data published in manuals, and to strongly distrust the so-called warning signs. Haven't blown up a rifle yet, following that rule.
