Chiming in again here...i guess I'm starting to get on board with scope eyes theory about being able to get away with this only with light bullets of short bearing surface on account that even though his loads simply have to be wildly overpressure per saami specs, the "area under the curve" of that peak maybe isn't as much and that's why he's not getting primers popping out or bolts froze shut (or embedded in his cranium)
it would make sense that it's not just about peak psi but how long said psi is sustained for.
when I consider what rifles have to be proven safe with, proof loads, and when I read about what they did to prove the strength of the weatherby mark 5 action back in the day (lodge a bullet down the bore then fire a proof load cartridge out of it...gun was inoperable after but the action did not blow up if i recall...estimated 200kpsi) I must conclude that the 65 kpsi limit applies to brass integrity and smooth operability more than the actions ability to handle it. The wby m5 is indeed strong but it's also been established its not stronger than most others by that huge of a margin. Rarely do all 9 lugs truly lock up, if anything is suspect a well made 2 lug to be more failsafe. The only times I've got sticky bolts or blown a primer where with 180+ grain bullets in my 300 win. I've also observed the so called pressure signs on factory ammo, again now that I think of it with 180s at a very anemic 2960 FPS but ran 150 gr handloads to 3450 with no signs. I believe those loads MUST have hit greater pressure despite this, and it wasn't a problem.
scope eye...I think you're really onto something with this theory.
I'm still nervous for your sake about these numbers you post, same with your 300 rum post. Impressive as all get out, I believe you and your chrono are telling the truth, I know you have way more experience than I do. But both my brain and my gut are saying YIKES!
my brain and my gut are often wrong too. I need to revisit some light weight at warp experimentation. Safety of course.