Pressure

At what pressure in psi do these signs start to appear?

The SAAMI Max Average Pressure differs greatly from cartridge to cartridge.

For example, the 280 Remington has an MAP of 60K psi while the 280 AI (same brass) has an MAP of 65K.

How does the brass/primers know to show signs of over pressure in the 280 just over 60K and hold off on these signs in the AI until 65K?

What about some of these low pressure rounds like the 6.5 Swede (51K) and the 7.62 x 39 (45K), at what psi are these low pressure rounds going to show signs of pressure and how do they know what SAAMI has set their limits at?
 
I don't know about the last two you mentioned but the difference in the AI cases are the shoulder and less case taper. The AI cases really hide pressure and you usually lose the primer pockets before you see normal pressure signs with out chonographing your load .
 
I was going over pressure on my 280ai. My rifle action is a Rem 700, and it shows pressure by a shinny wipe mark on the case head.
 
truck driver":3uv7obvt said:
I don't know about the last two you mentioned but the difference in the AI cases are the shoulder and less case taper. The AI cases really hide pressure and you usually lose the primer pockets before you see normal pressure signs with out chonographing your load .

Ok, how about the 280 (60k), 30-06 (60k) , 25-06 (63k) and the 270 (65k)?

How do these pressure signs know to show up at different pressures in almost identical cartridges.

At what psi would these pressure signs appear in each of the above cartridges?
 
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