My post had nothing to do with rifles. My rifle showed no signs of pressure either at 3200 FPS. The fact of the matter is your barrel will go fast pushing them that quick and the brass wont last long. I personally don't believe your primer pockets are still intact after 11 firings shooting it at that speed. Velocity = pressure as far as I'm concerned and those cases can only take so much until they go south. A 243 AI is already a barrel burner so enjoy replacing your barrel after 800 rounds shooting them that fast. Have a nice day.
The physical characteristics of the entire system influence what is safe and what is not, including the rifle. Chamber dimensions are different, even among 'identical' factory models. Headspace varies. Transition to the lands varies. Tool marks can have an influence, etc., etc.
Yes, chamber pressure and velocity are related but the relationship is not direct. If the two were directly related, then the muzzle velocity produced by two different powders loaded to produce the same chamber pressure would be the same. We all know that is not the case. Pressure over time is what causes the difference in velocity between different powders (H4350 v. RL-15, for example) producing the same chamber pressure, all other things being equal. That's why we have a bazillion different powders from which to choose when we work up loads for our rifles.
As for barrel wear, velocity is not the culprit here. Barrels get 'shot out' by pressure and heat, not the velocity of the projectile, and the area of wear that separates a new barrel from one that is 'shot out' is the area immediately in front of the chamber. One can turn a brand new barrel into junk very quickly by feeding it a steady diet of maximum pressure loads using a powder that is too fast for the application - even faster if the powder has a high heat of explosion. Velocity will be comparatively low in this scenario but the barrel will wear quickly. It is well known that using a slow-burning powder with a low heat of explosion, like H1000, is less erosive to a barrel's throat and will result in longer barrel life. Interestingly, H1000 produces outstanding velocities in many applications, heavy bullet .243 and .243 AI loads among them.
I'm just under 1,000 rounds on my barrel and she still stacks 'em. There's some throat wear, of course, but I figure I'll get another 200-300 before it's time for another tube.
As for brass life, I don't know what to tell you. Maybe my Lapua brass is magic. Glad I bought a few boxes.