There have been comments and articles for years like the one I reference here:
"Actually, there is a little truth to the "pressure spikes" in the 7mm Remington Magnum. I have gotten the story straight from some of the guys in ballistic labs.
For some unknown reason, the 7mm RM's pressures do vary more than in some other cartridges. You really can't call them pressure spikes, as in all of a sudden a case blows a primer or something like that. But the pressure do vary enough, especially with certain powders, that the SAAMI pressure standards were reduced somewhat from the original levels. And that's why the SAAMI average pressure is 61,000 rather than the 64-65,000 of most other belted magnums."
Mule Deer.
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