The error is in the misconception that commercial .308 is loaded to substantially higher chamber pressure than military 7.62 NATO. It is not.
The Army is not a member of SAAMI and did not adopt the term "CUP" for pressure measurements by crusher gauge. So 7.62 pressure is determined by a crusher gauge but still reported in psi from where the gauge was calibrated by hydraulic pressure or dead load. Which gives a lower number than a piezoelectric transducer that is now taken as Gospel for "psi."
Put a 7.62 in a piezo setup and it will read (nearly) as high as a .308, which is what you see in Quickload.
|