"Reading" primers for pressure.

[Moose83]

So... how reliable is reading primers as a sign of pressure? I keep reading on here about "flat" primers being a sign of higher pressure, yet other sources I've read indicate that primer condition has no correlation to pressure signs, flattened primers are more of an indication of chamber dimensions (I may be mis remembering this part). Case in point... I loaded 5 rounds of .243 with the 95gr BT starting at 40gr up to 44gr of Accurate 3100. All 5 cases primer condition was identical... flattened. Bolt lift and extraction on all 5 was easy and smooth, but the 44gr load looked like it had a very slight ejector swipes. What says Rokslide? How many of you go by primer condition to gauge pressures?

 

[greyghostnw]

Those primers look far from flat from my house and mine usually look flattish… im 2 tenths in a node below my max…In my pressure testing the case base will have raised plunger marks that first show initial pressure therefore becoming trash as you will never be able to size brass back properly in that state again with headspace gauge and caliper because your reading the raised area and will think your fls die needs adjusting but you never should once your brass has fully expanded in firings.

 

[49ereric]

What he said ^

 

[rickyw]

Yeah those look pretty good

 

[mtnbound]

So... how reliable is reading primers as a sign of pressure? I keep reading on here about "flat" primers being a sign of higher pressure, yet other sources I've read indicate that primer condition has no correlation to pressure signs, flattened primers are more of an indication of chamber dimensions (I may be mis remembering this part). Case in point... I loaded 5 rounds of .243 with the 95gr BT starting at 40gr up to 44gr of Accurate 3100. All 5 cases primer condition was identical... flattened. Bolt lift and extraction on all 5 was easy and smooth, but the 44gr load looked like it had a very slight ejector swipes. What says Rokslide? How many of you go by primer condition to gauge pressures?View attachment 975735

I never rely on just one indicator of possible pressure, and those primers look ok to me.