This is pretty close. The strain gauge is a electro-conductive sheet whose conductivity is a function of strain within itself. The sheet is attached to thebarrel with adhesive, and when the gun is fired, pressures expand the barrel stretching the electro-conductive sheet. If one can calibrate just how much the barrel was strained at a given point in time then it is possible to calculate pressure within the barrel at that location and time by knowing the dimensional properties of the barrel and the physical properties of steel of which the barrel is composed.

A strain gage does not take a direct measurement of pressure. Furthermore, it is unreliable as a measurement tool for pressure. The usefulness of a strain gage is more in "relational" data. That said. If it is calibrated with actual direct pressure measurement on the barrel on which they are installed, they can produce reliable data for the calculation of pressure.

Wolfhound76, if Randy is screwing around with strain guages, then don't trust any thing he tells you about them or the pressures he claims he is measuring. He's a friend of yours and I appreciate that, but I am correct in saying what I am saying, it simply will not hold in court against BPI'sdirect measurementpressure testing.

By the way, if you want to contribute beneficially to this thread, you could help me get data on the grades of steel used in the Spanish barrels, also Knights, NEF's, GM's, Whites, and T/C's. I can only assume Randy has this data. Will help us get this data? I need minimum yield strength and minimum tensile strength for the steels each uses.

Happy Hunting, Phil