That statement, particularly that in bold, is not true at all. Obviously whoever wrote that is selling/pushing the RSI system. Dr. Oehler's information with the M43 specifically states the measured psi's are relative to the test firearm only. That is the same with pressure test barrels used by ammunition manufacturer's, both CUP and transducer. It is also true of any pressure measurements by the RSI system. They are relevant only to the test barrel unless a "correction factor" is used based on measurement of pressure with "reference ammunition" in that test barrel.
The pressures the manuals or other sources record and then publish using their their test barrels is most likely not the same pressure the same ammunition will generate in your rifle. Heck, the pressures generated do not even agree test barrel to test barrel. That's why "reference" ammunition is used as measurement standard to get a "correction factor". I also use "reference" ammunition to get a correction factor. I use a specific lot of factory ammunition that a technician provided me the pressure of when it was tested in their peizo-transducer. Thus the difference between the M43 measured psi and the factory measured psi is the "correction factor". That is how it is done to SAAMI test specifications.
BTW, the RSI system uses the same strain gauges measurements as the Oehler M43 does. The gauge, which is placed over the chamber (I place mine at the SAAMI designated measuring spot), measures the "stress" (electronic impulse) created in the gauge by the pressure placed on the barrel. The computer program then measures the level of stress over the time/pressure curve converting that to psi. Complete information is input into the program including the calibration of the gauge. Dr. Oehler did and extensive test installing on a CUP test rifle 2 separate peizo-transducers, a case mouth transducer, a Gauge for a M83 and a gauge for a M43. That is 6 different pressure measurements for each shot tested. The M83 (a commercial system which is extensively used in the munitions industry) and the M43 gave consistently comparable pressure measurements to the other methods including the CUP method. Keep in mind the CUP method will only measure the peak pressure and does not give any other pressure information.
Now for the doubting Thomas's please then explain why with the Hodgdon listed max load of 57.5 gr under the 178 gr bullet left 3 of the cases with swollen primer pockets which is a definite sign of excessive pressure in any load manual. The M43 masured that load's psi at 69,000+ which is excessive pressure for any 30-06 in any loading manual and would be certainly in line with swollen primer pockets.
Of course it's possible the measured data was off the 1st test. However, I checked everything out and had fired a test string of known ammunition performance prior to the 2nd test which gave psi's and velocity in the normal range of ES for that ammunition. Also the reduced loads of H4350 with the same 178 gr bullet produced lower psi's commensurate with the 1st tests results.
Additionally, I have five different bullets (178 ELD-X, Sierra 175 MK, Hornady 180 SPBT, Sierra 180 SPBT and Speer 180 SP) all loaded over 55.3 gr H4350 which is max Hornady #8 and #10 Manual's charge of H4350 for 175 - 180 gr bullets in the 30-06. The same W_W cases and Federal primers are used as in the previous tests. Also I will test the factory "reference" ammunition (Federal) and the same previous tested ammunition (LC M72 Match). All test strings are 10 shots (SAAMI test standard) unless pressures are excessive and I stop the test. I will test before the week is out, weather permitting, and then we shall see.