I may be confused, but from your posts, my understanding is that you think the 280AI being referred to is a wildcat, and that's why you quoted the 280Rem pressure specification. If that's not what you mean, then I apologize. The 280AI being referred to is not a wildcat. It is a standardized cartridge that was spec'd by Nosler and recognized by SAAMI. It is not what you would get if you Ackley improved a 280 Rem. An Ackley Improved 280Rem is the wildcat that people once referred to as a "280AI", but it is not what was being discussed. The pressure specified by Nosler, and published in SAAMI is 65ksi. This pressure specification has absolutely nothing to do with the shape of the case. It is a pressure than rifle manufactures need to know that factory ammo could produce. That way rifle designers can make wise choices about what rifles they chamber for a 280AI. Most, if not all, modern bolt action rifles will handle well in access of 65ksi. Most of your ammunition related mishaps aren't because the action couldn't take it, they're usually because the brass couldn't take it. The brass case is the seal, and when it goes, bad things happen and pressure goes places that it was never intended to go, including your face. This is why the 7mm Back Country doesn't require special rifle designs when bolt actions are concerned. Most of the actions out there are already plenty strong. AR's, other semi-autos, lever actions, actions with small diameters, and actions with very limited recoil lug surface, will all need closer inspection by engineers than most of our common bolt actions will. Many of our cartridges with pressure specifications below 65ksi, and particularly those below 60ksi, were spec'd with lower pressure because they were intended for use in a certain rifle that wasn't suited to high pressure. If you have a rifle that a manufacture chambers for 280AI, then you could load any case with that head diameter from a 243Win, to a 7x57, to a 30-06 Springfield up to 65ksi with zero problems at all. You would experience increased performance, and nothing else. But the ammunition manufacturers cannot do this, because they don't know what rifle you're loading it in. You could shoot a 284Win in a Remington 700 loaded to 65ksi with no problem, but if you loaded it in your Winchester lever action, you'd be asking for serious trouble.
^^^All this to say that the 280AI truly has a SAAMI pressure spec of 65ksi, but it has nothing to do with with modifications to the case that Nosler made. So when you say "if the same principle/concept applies then a 270 AI should be 70,000psi" I really have no idea what principle you're referring to. Maybe I missed the post where such a principle was suggested. No such principle exists, but the 280AI is in fact a 65ksi cartridge. That is important to rifle manufacturers, ammunition manufacturers, and people making reloading manuals. To someone who is going to load all the up to pressure signs, it really doesn't matter too much. That person doesn't know what pressure they're at, but it's likely between 65ksi and 70ksi regardless of cartridge.
On a slightly side note, the first place our brass tends to go is the primer pocket. This does give some cartridges the ability to be loaded slightly hotter than others. Magnum case heads will take slightly more pressure before the primer pocket leaks or gets loose, and so do standard case heads with small primer pockets.
. Good luck being around when that's going to take places.
