Over the years at Accurate Reloading forum I have endured hundreds for flame wars between Denton Bramwell "Denton" measure pressure advocate and Glenn Rice "Hot Core" measure brass advocate.
I think they are both electrical engineers, as am I.
After that much arguing, it is a stylized debate.
I have my own flow chart:
1) If I were to sell ammo, I would measure pressure* and develop
loads to SAAMI registered pressures.
2) If I am loading for a gun that is weaker than the brass, like a revolver with .040" thick chamber walls and a rimmed case, just don't exceed max loads in load books, where pressure was measured.
3) If I am loading for a gun stronger than the brass, load up to the threshold of short brass life, and reduce by at least a safety margin to find the max load for my gun.
* With CEA-O6-250UW-350 strain gauges and AD8554 op amps in an instrumentation amplifier configuration, I can get great accuracy in measuring the strain on barrel steel locally.
Instrumentation amplifier - Wikipedia, the free encyclopedia
One problem I have is the precision of where the gauge is epoxied onto the barrel.
Another problem I have is that the barrel is not a uniform thickness thin wall long tube. It is an open ended tapered tube. That gets me into Roark's book on stress vs stain on open ended tubes:
Amazon.com: Roark's Formulas for Stress and Strain: Warren Young, Richard Budynas: Books
I think Denton buys amplifiers, and calls mine "home brew", but mine are more accurate. The inaccuracy is in the epoxy, position, thickness, and formula for tapered open ended barrels. Then there is the error of value used for Young's Modulus for steel in the barrel.
I have a friend who has by passed this, and gone to pressure receiver and transducers.
That still leaves errors for the handloader, in that it misses the individuality of the gun and the error of the pressure registered with SAAMI.